diff --git a/src/calibre/customize/__init__.py b/src/calibre/customize/__init__.py
index 2625c569d9..bc3d4fef92 100644
--- a/src/calibre/customize/__init__.py
+++ b/src/calibre/customize/__init__.py
@@ -133,7 +133,7 @@ class Plugin(object):  # {{{
         True if the user clicks OK, False otherwise. The changes are
         automatically applied.
         '''
-        from PyQt5.Qt import QDialog, QDialogButtonBox, QVBoxLayout, \
+        from qt.core import QDialog, QDialogButtonBox, QVBoxLayout, \
                 QLabel, Qt, QLineEdit
         from calibre.gui2 import gprefs
 
@@ -148,7 +148,7 @@ class Plugin(object):  # {{{
             if geom is None:
                 config_dialog.resize(config_dialog.sizeHint())
             else:
-                from PyQt5.Qt import QApplication
+                from qt.core import QApplication
                 QApplication.instance().safe_restore_geometry(config_dialog, geom)
 
         button_box.accepted.connect(config_dialog.accept)
diff --git a/src/calibre/customize/zipplugin.py b/src/calibre/customize/zipplugin.py
index 6f72f2c259..ec5aeaeaeb 100644
--- a/src/calibre/customize/zipplugin.py
+++ b/src/calibre/customize/zipplugin.py
@@ -70,7 +70,7 @@ def get_icons(zfp, name_or_list_of_names):
                 If a single path is passed in the return value will
                 be A QIcon.
     '''
-    from PyQt5.Qt import QIcon, QPixmap
+    from qt.core import QIcon, QPixmap
     names = name_or_list_of_names
     ans = get_resources(zfp, names)
     if isinstance(names, string_or_bytes):
diff --git a/src/calibre/db/cache.py b/src/calibre/db/cache.py
index 956146fc98..801ae6e4a6 100644
--- a/src/calibre/db/cache.py
+++ b/src/calibre/db/cache.py
@@ -724,7 +724,7 @@ class Cache(object):
                 return
             ret = buf.getvalue()
             if as_image:
-                from PyQt5.Qt import QImage
+                from qt.core import QImage
                 i = QImage()
                 i.loadFromData(ret)
                 ret = i
diff --git a/src/calibre/devices/kobo/kobotouch_config.py b/src/calibre/devices/kobo/kobotouch_config.py
index fd24ba62ff..0c5b3b507b 100644
--- a/src/calibre/devices/kobo/kobotouch_config.py
+++ b/src/calibre/devices/kobo/kobotouch_config.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from PyQt5.Qt import (QWidget, QLabel, QGridLayout, QLineEdit, QVBoxLayout,
+from qt.core import (QWidget, QLabel, QGridLayout, QLineEdit, QVBoxLayout,
                       QDialog, QDialogButtonBox, QCheckBox, QPushButton)
 
 from calibre.gui2.device_drivers.tabbed_device_config import TabbedDeviceConfig, DeviceConfigTab, DeviceOptionsGroupBox
diff --git a/src/calibre/ebooks/conversion/plugins/pdf_output.py b/src/calibre/ebooks/conversion/plugins/pdf_output.py
index 2345c2501f..66ff9d6060 100644
--- a/src/calibre/ebooks/conversion/plugins/pdf_output.py
+++ b/src/calibre/ebooks/conversion/plugins/pdf_output.py
@@ -148,8 +148,8 @@ class PDFOutput(OutputFormatPlugin):
         # Ensure Qt is setup to be used with WebEngine
         # specialize_options is called early enough in the pipeline
         # that hopefully no Qt application has been constructed as yet
-        from PyQt5.QtWebEngineCore import QWebEngineUrlScheme
-        from PyQt5.QtWebEngineWidgets import QWebEnginePage  # noqa
+        from qt.webengine import QWebEngineUrlScheme
+        from qt.webengine import QWebEnginePage  # noqa
         from calibre.gui2 import must_use_qt
         from calibre.constants import FAKE_PROTOCOL
         scheme = QWebEngineUrlScheme(FAKE_PROTOCOL.encode('ascii'))
diff --git a/src/calibre/ebooks/covers.py b/src/calibre/ebooks/covers.py
index 3faae54842..0ede115405 100644
--- a/src/calibre/ebooks/covers.py
+++ b/src/calibre/ebooks/covers.py
@@ -12,7 +12,7 @@ from math import ceil, sqrt, cos, sin, atan2
 from polyglot.builtins import iteritems, itervalues, map, zip, string_or_bytes
 from itertools import chain
 
-from PyQt5.Qt import (
+from qt.core import (
     QImage, Qt, QFont, QPainter, QPointF, QTextLayout, QTextOption,
     QFontMetrics, QTextCharFormat, QColor, QRect, QBrush, QLinearGradient,
     QPainterPath, QPen, QRectF, QTransform, QRadialGradient
@@ -727,7 +727,7 @@ def generate_masthead(title, output_path=None, width=600, height=60, as_qimage=F
 
 
 def test(scale=0.25):
-    from PyQt5.Qt import QLabel, QPixmap, QMainWindow, QWidget, QScrollArea, QGridLayout
+    from qt.core import QLabel, QPixmap, QMainWindow, QWidget, QScrollArea, QGridLayout
     from calibre.gui2 import Application
     app = Application([])
     mi = Metadata('Unknown', ['Kovid Goyal', 'John & Doe', 'Author'])
diff --git a/src/calibre/ebooks/html/to_zip.py b/src/calibre/ebooks/html/to_zip.py
index f5805136bd..be8a7b5e8f 100644
--- a/src/calibre/ebooks/html/to_zip.py
+++ b/src/calibre/ebooks/html/to_zip.py
@@ -73,7 +73,7 @@ every time you add an HTML file to the library.\
         True if the user clicks OK, False otherwise. The changes are
         automatically applied.
         '''
-        from PyQt5.Qt import (QDialog, QDialogButtonBox, QVBoxLayout,
+        from qt.core import (QDialog, QDialogButtonBox, QVBoxLayout,
                 QLabel, Qt, QLineEdit, QCheckBox)
 
         config_dialog = QDialog(parent)
diff --git a/src/calibre/ebooks/oeb/display/webview.py b/src/calibre/ebooks/oeb/display/webview.py
index c563009ddc..0ecf4fd341 100644
--- a/src/calibre/ebooks/oeb/display/webview.py
+++ b/src/calibre/ebooks/oeb/display/webview.py
@@ -50,7 +50,7 @@ def load_as_html(html):
 def load_html(path, view, codec='utf-8', mime_type=None,
               pre_load_callback=lambda x:None, path_is_html=False,
               force_as_html=False, loading_url=None):
-    from PyQt5.Qt import QUrl, QByteArray
+    from qt.core import QUrl, QByteArray
     if mime_type is None:
         mime_type = guess_type(path)[0]
         if not mime_type:
diff --git a/src/calibre/ebooks/oeb/polish/check/css.py b/src/calibre/ebooks/oeb/polish/check/css.py
index 5ef001221b..74ffe3b85a 100644
--- a/src/calibre/ebooks/oeb/polish/check/css.py
+++ b/src/calibre/ebooks/oeb/polish/check/css.py
@@ -13,8 +13,8 @@ try:
     from PyQt5 import sip
 except ImportError:
     import sip
-from PyQt5.Qt import QApplication, QEventLoop, pyqtSignal
-from PyQt5.QtWebEngineWidgets import (
+from qt.core import QApplication, QEventLoop, pyqtSignal
+from qt.webengine import (
     QWebEnginePage, QWebEngineProfile, QWebEngineScript
 )
 
diff --git a/src/calibre/ebooks/oeb/polish/check/images.py b/src/calibre/ebooks/oeb/polish/check/images.py
index 2ed25977d4..10cb4f1d86 100644
--- a/src/calibre/ebooks/oeb/polish/check/images.py
+++ b/src/calibre/ebooks/oeb/polish/check/images.py
@@ -32,7 +32,7 @@ class CMYKImage(BaseError):
     level = WARN
 
     def __call__(self, container):
-        from PyQt5.Qt import QImage
+        from qt.core import QImage
         from calibre.gui2 import pixmap_to_data
         ext = container.mime_map[self.name].split('/')[-1].upper()
         if ext == 'JPG':
diff --git a/src/calibre/ebooks/oeb/transforms/rasterize.py b/src/calibre/ebooks/oeb/transforms/rasterize.py
index ef4bfac94e..607f06f7ba 100644
--- a/src/calibre/ebooks/oeb/transforms/rasterize.py
+++ b/src/calibre/ebooks/oeb/transforms/rasterize.py
@@ -8,7 +8,7 @@ __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
 import os, re
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QByteArray, QBuffer, QIODevice, QColor, QImage, QPainter, QSvgRenderer)
 from calibre.ebooks.oeb.base import XHTML, XLINK
 from calibre.ebooks.oeb.base import SVG_MIME, PNG_MIME
diff --git a/src/calibre/ebooks/pdf/develop.py b/src/calibre/ebooks/pdf/develop.py
index ab9ff4db0c..eb75ced6b4 100644
--- a/src/calibre/ebooks/pdf/develop.py
+++ b/src/calibre/ebooks/pdf/develop.py
@@ -5,8 +5,8 @@
 
 import sys
 
-from PyQt5.Qt import QApplication, QUrl, QPageLayout, QPageSize, QMarginsF
-from PyQt5.QtWebEngineWidgets import QWebEnginePage
+from qt.core import QApplication, QUrl, QPageLayout, QPageSize, QMarginsF
+from qt.webengine import QWebEnginePage
 
 from calibre.gui2 import load_builtin_fonts, must_use_qt
 from calibre.utils.podofo import get_podofo
diff --git a/src/calibre/ebooks/pdf/html_writer.py b/src/calibre/ebooks/pdf/html_writer.py
index 5f2470ea17..c61e140ff0 100644
--- a/src/calibre/ebooks/pdf/html_writer.py
+++ b/src/calibre/ebooks/pdf/html_writer.py
@@ -14,11 +14,11 @@ from collections import namedtuple
 from html5_parser import parse
 from io import BytesIO
 from itertools import count, repeat
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QMarginsF, QObject, QPageLayout, Qt, QTimer, QUrl, pyqtSignal
 )
-from PyQt5.QtWebEngineCore import QWebEngineUrlRequestInterceptor
-from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineProfile
+from qt.webengine import QWebEngineUrlRequestInterceptor
+from qt.webengine import QWebEnginePage, QWebEngineProfile
 
 from calibre import detect_ncpus, human_readable, prepare_string_for_xml
 from calibre.constants import __version__, iswindows
diff --git a/src/calibre/ebooks/pdf/image_writer.py b/src/calibre/ebooks/pdf/image_writer.py
index 4ff0110ed7..a9a4e82376 100644
--- a/src/calibre/ebooks/pdf/image_writer.py
+++ b/src/calibre/ebooks/pdf/image_writer.py
@@ -3,7 +3,7 @@
 # License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import QMarginsF, QPageLayout, QPageSize, QSizeF
+from qt.core import QMarginsF, QPageLayout, QPageSize, QSizeF
 
 from calibre.constants import filesystem_encoding
 from calibre.ebooks.pdf.render.common import cicero, cm, didot, inch, mm, pica
diff --git a/src/calibre/ebooks/pdf/pageoptions.py b/src/calibre/ebooks/pdf/pageoptions.py
index c78a58c0a3..7d74452fce 100644
--- a/src/calibre/ebooks/pdf/pageoptions.py
+++ b/src/calibre/ebooks/pdf/pageoptions.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QPrinter
+from qt.core import QPrinter
 
 UNITS = {
             'millimeter' : QPrinter.Unit.Millimeter,
diff --git a/src/calibre/ebooks/pdf/render/gradients.py b/src/calibre/ebooks/pdf/render/gradients.py
index 5cdac4e624..86ad45391f 100644
--- a/src/calibre/ebooks/pdf/render/gradients.py
+++ b/src/calibre/ebooks/pdf/render/gradients.py
@@ -10,7 +10,7 @@ import sys, copy
 from polyglot.builtins import map, range
 from collections import namedtuple
 
-from PyQt5.Qt import QLinearGradient, QPointF
+from qt.core import QLinearGradient, QPointF
 try:
     from PyQt5 import sip
 except ImportError:
diff --git a/src/calibre/ebooks/pdf/render/graphics.py b/src/calibre/ebooks/pdf/render/graphics.py
index 14c33f5fe3..158c7617a7 100644
--- a/src/calibre/ebooks/pdf/render/graphics.py
+++ b/src/calibre/ebooks/pdf/render/graphics.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 from math import sqrt
 from collections import namedtuple
 
-from PyQt5.Qt import (
+from qt.core import (
     QBrush, QPen, Qt, QPointF, QTransform, QPaintEngine, QImage)
 
 from calibre.ebooks.pdf.render.common import (
diff --git a/src/calibre/ebooks/pdf/render/serialize.py b/src/calibre/ebooks/pdf/render/serialize.py
index e9fa01a56e..7fe0d9a25f 100644
--- a/src/calibre/ebooks/pdf/render/serialize.py
+++ b/src/calibre/ebooks/pdf/render/serialize.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import hashlib, numbers
 from polyglot.builtins import map, iteritems
 
-from PyQt5.Qt import QBuffer, QByteArray, QImage, Qt, QColor, qRgba, QPainter
+from qt.core import QBuffer, QByteArray, QImage, Qt, QColor, qRgba, QPainter
 
 from calibre.constants import (__appname__, __version__)
 from calibre.ebooks.pdf.render.common import (
diff --git a/src/calibre/ebooks/render_html.py b/src/calibre/ebooks/render_html.py
index e8dbafc843..20f012fab4 100644
--- a/src/calibre/ebooks/render_html.py
+++ b/src/calibre/ebooks/render_html.py
@@ -6,10 +6,10 @@
 import os
 import sys
 
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QMarginsF, QPageLayout, QPageSize, Qt, QTimer, QUrl
 )
-from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineScript
+from qt.webengine import QWebEnginePage, QWebEngineScript
 
 from calibre.ebooks.metadata.pdf import page_images
 from calibre.gui2 import must_use_qt
diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index a53a48673b..ea4e94e9fe 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -13,14 +13,13 @@ import threading
 from contextlib import contextmanager
 from threading import Lock, RLock
 
-from PyQt5.Qt import (
+from qt.core import (
     QT_VERSION, QApplication, QBuffer, QByteArray, QCoreApplication, QDateTime,
     QDesktopServices, QDialog, QEvent, QFileDialog, QFileIconProvider, QFileInfo, QPalette,
     QFont, QFontDatabase, QFontInfo, QFontMetrics, QIcon, QLocale, QColor,
     QNetworkProxyFactory, QObject, QSettings, QSocketNotifier, QStringListModel, Qt,
-    QThread, QTimer, QTranslator, QUrl, pyqtSignal, QIODevice, QDialogButtonBox
+    QThread, QTimer, QTranslator, QUrl, pyqtSignal, QIODevice, QDialogButtonBox, QStyle
 )
-from PyQt5.QtWidgets import QStyle  # Gives a nicer error message than import from Qt
 
 from calibre import as_unicode, prints
 from calibre.constants import (
@@ -1171,14 +1170,14 @@ class Application(QApplication):
 
     @property
     def current_custom_colors(self):
-        from PyQt5.Qt import QColorDialog
+        from qt.core import QColorDialog
 
         return [col.getRgb() for col in
                     (QColorDialog.customColor(i) for i in range(QColorDialog.customCount()))]
 
     @current_custom_colors.setter
     def current_custom_colors(self, colors):
-        from PyQt5.Qt import QColorDialog
+        from qt.core import QColorDialog
         num = min(len(colors), QColorDialog.customCount())
         for i in range(num):
             QColorDialog.setCustomColor(i, QColor(*colors[i]))
@@ -1386,7 +1385,7 @@ def elided_text(text, font=None, width=300, pos='middle'):
     rendered, replacing characters from the left, middle or right (as per pos)
     of the string with an ellipsis. Results in a string much closer to the
     limit than Qt's elidedText().'''
-    from PyQt5.Qt import QFontMetrics, QApplication
+    from qt.core import QFontMetrics, QApplication
     if font is None:
         font = QApplication.instance().font()
     fm = (font if isinstance(font, QFontMetrics) else QFontMetrics(font))
diff --git a/src/calibre/gui2/actions/__init__.py b/src/calibre/gui2/actions/__init__.py
index 411660edb3..88626ad158 100644
--- a/src/calibre/gui2/actions/__init__.py
+++ b/src/calibre/gui2/actions/__init__.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 from functools import partial
 from zipfile import ZipFile
 
-from PyQt5.Qt import (QToolButton, QAction, QIcon, QObject, QMenu,
+from qt.core import (QToolButton, QAction, QIcon, QObject, QMenu,
         QKeySequence)
 
 from calibre import prints
diff --git a/src/calibre/gui2/actions/add.py b/src/calibre/gui2/actions/add.py
index 5ada7f0a74..778b23e56c 100644
--- a/src/calibre/gui2/actions/add.py
+++ b/src/calibre/gui2/actions/add.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os
 from collections import defaultdict
 from functools import partial
-from PyQt5.Qt import QApplication, QDialog, QPixmap, QTimer
+from qt.core import QApplication, QDialog, QPixmap, QTimer
 
 from calibre import as_unicode, guess_type
 from calibre.constants import iswindows
diff --git a/src/calibre/gui2/actions/annotate.py b/src/calibre/gui2/actions/annotate.py
index 31151f3c94..1283662082 100644
--- a/src/calibre/gui2/actions/annotate.py
+++ b/src/calibre/gui2/actions/annotate.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import pyqtSignal, QModelIndex, QThread, Qt
+from qt.core import pyqtSignal, QModelIndex, QThread, Qt
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
diff --git a/src/calibre/gui2/actions/author_mapper.py b/src/calibre/gui2/actions/author_mapper.py
index e1d2ea9a75..3616901b3b 100644
--- a/src/calibre/gui2/actions/author_mapper.py
+++ b/src/calibre/gui2/actions/author_mapper.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import QDialog
+from qt.core import QDialog
 from calibre.gui2 import gprefs
 from calibre.gui2.actions import InterfaceAction
 from polyglot.builtins import iteritems, map, range
diff --git a/src/calibre/gui2/actions/browse_annots.py b/src/calibre/gui2/actions/browse_annots.py
index f055789ac3..88731ed551 100644
--- a/src/calibre/gui2/actions/browse_annots.py
+++ b/src/calibre/gui2/actions/browse_annots.py
@@ -4,7 +4,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-from PyQt5.Qt import Qt
+from qt.core import Qt
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
diff --git a/src/calibre/gui2/actions/catalog.py b/src/calibre/gui2/actions/catalog.py
index 19996655f5..5efb4088d3 100644
--- a/src/calibre/gui2/actions/catalog.py
+++ b/src/calibre/gui2/actions/catalog.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import re, os, shutil, errno
 
-from PyQt5.Qt import QModelIndex
+from qt.core import QModelIndex
 
 from calibre.gui2 import choose_dir, error_dialog, warning_dialog
 from calibre.gui2.tools import generate_catalog
diff --git a/src/calibre/gui2/actions/choose_library.py b/src/calibre/gui2/actions/choose_library.py
index 5d9ae42f32..2499722dac 100644
--- a/src/calibre/gui2/actions/choose_library.py
+++ b/src/calibre/gui2/actions/choose_library.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os, posixpath, weakref, sys
 from functools import partial
 
-from PyQt5.Qt import (QMenu, Qt, QInputDialog, QToolButton, QDialog,
+from qt.core import (QMenu, Qt, QInputDialog, QToolButton, QDialog,
         QDialogButtonBox, QGridLayout, QLabel, QLineEdit, QIcon, QSize,
         QCoreApplication, pyqtSignal, QVBoxLayout, QTimer, QAction)
 
diff --git a/src/calibre/gui2/actions/convert.py b/src/calibre/gui2/actions/convert.py
index 946c72d50a..5f494ac67e 100644
--- a/src/calibre/gui2/actions/convert.py
+++ b/src/calibre/gui2/actions/convert.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os
 from functools import partial
 
-from PyQt5.Qt import QModelIndex, QTimer
+from qt.core import QModelIndex, QTimer
 
 from calibre.gui2 import error_dialog, Dispatcher, gprefs
 from calibre.gui2.tools import convert_single_ebook, convert_bulk_ebook
diff --git a/src/calibre/gui2/actions/copy_to_library.py b/src/calibre/gui2/actions/copy_to_library.py
index 762a5d3f62..1d61543a25 100644
--- a/src/calibre/gui2/actions/copy_to_library.py
+++ b/src/calibre/gui2/actions/copy_to_library.py
@@ -12,7 +12,7 @@ from threading import Thread
 from contextlib import closing
 from collections import defaultdict
 
-from PyQt5.Qt import (
+from qt.core import (
     QToolButton, QDialog, QGridLayout, QIcon, QLabel, QDialogButtonBox,
     QApplication, QLineEdit, QHBoxLayout, QFormLayout, QCheckBox, QWidget,
     QScrollArea, QVBoxLayout, Qt, QListWidgetItem, QListWidget, QSize, QAbstractItemView)
diff --git a/src/calibre/gui2/actions/delete.py b/src/calibre/gui2/actions/delete.py
index 109aeea85c..fc96e12bdc 100644
--- a/src/calibre/gui2/actions/delete.py
+++ b/src/calibre/gui2/actions/delete.py
@@ -10,7 +10,7 @@ import errno, os
 from functools import partial
 from collections import Counter
 
-from PyQt5.Qt import QObject, QTimer, QModelIndex, QDialog
+from qt.core import QObject, QTimer, QModelIndex, QDialog
 
 from calibre.constants import ismacos
 from calibre.gui2 import error_dialog, question_dialog
diff --git a/src/calibre/gui2/actions/device.py b/src/calibre/gui2/actions/device.py
index af8da7c7e9..c2cfcad581 100644
--- a/src/calibre/gui2/actions/device.py
+++ b/src/calibre/gui2/actions/device.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QIcon, QMenu, QTimer, QToolButton, pyqtSignal
+from qt.core import QIcon, QMenu, QTimer, QToolButton, pyqtSignal
 
 from calibre.gui2 import info_dialog, question_dialog
 from calibre.gui2.actions import InterfaceAction
diff --git a/src/calibre/gui2/actions/edit_metadata.py b/src/calibre/gui2/actions/edit_metadata.py
index c7c1a7e86f..e9f7ecb60a 100644
--- a/src/calibre/gui2/actions/edit_metadata.py
+++ b/src/calibre/gui2/actions/edit_metadata.py
@@ -11,7 +11,7 @@ import os
 import shutil
 from functools import partial
 from io import BytesIO
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QDialog, QIcon, QMenu, QMimeData, QModelIndex, QTimer, QUrl
 )
 
diff --git a/src/calibre/gui2/actions/embed.py b/src/calibre/gui2/actions/embed.py
index f1b54a13c1..79f0f18d43 100644
--- a/src/calibre/gui2/actions/embed.py
+++ b/src/calibre/gui2/actions/embed.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
 
-from PyQt5.Qt import QTimer, QProgressDialog, Qt
+from qt.core import QTimer, QProgressDialog, Qt
 
 from calibre import force_unicode
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/actions/fetch_news.py b/src/calibre/gui2/actions/fetch_news.py
index 0db1590fdd..118b4c6104 100644
--- a/src/calibre/gui2/actions/fetch_news.py
+++ b/src/calibre/gui2/actions/fetch_news.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import gc
 from functools import partial
 
-from PyQt5.Qt import Qt
+from qt.core import Qt
 
 from calibre.gui2 import Dispatcher
 from calibre.gui2.tools import fetch_scheduled_recipe
diff --git a/src/calibre/gui2/actions/help.py b/src/calibre/gui2/actions/help.py
index e8bf9832e5..ee7d045f69 100644
--- a/src/calibre/gui2/actions/help.py
+++ b/src/calibre/gui2/actions/help.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre.gui2 import open_url
 from calibre.gui2.actions import InterfaceAction
diff --git a/src/calibre/gui2/actions/mark_books.py b/src/calibre/gui2/actions/mark_books.py
index 962f621719..9146386ce0 100644
--- a/src/calibre/gui2/actions/mark_books.py
+++ b/src/calibre/gui2/actions/mark_books.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
 
-from PyQt5.Qt import QTimer, QApplication, Qt, QEvent
+from qt.core import QTimer, QApplication, Qt, QEvent
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
diff --git a/src/calibre/gui2/actions/plugin_updates.py b/src/calibre/gui2/actions/plugin_updates.py
index f904970e5b..ca179b434f 100644
--- a/src/calibre/gui2/actions/plugin_updates.py
+++ b/src/calibre/gui2/actions/plugin_updates.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Grant Drake <grant.drake@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QApplication, Qt, QIcon
+from qt.core import QApplication, Qt, QIcon
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.plugin_updater import (PluginUpdaterDialog,
                                                  FILTER_ALL, FILTER_UPDATE_AVAILABLE)
diff --git a/src/calibre/gui2/actions/polish.py b/src/calibre/gui2/actions/polish.py
index a747bff0a5..15f66cf543 100644
--- a/src/calibre/gui2/actions/polish.py
+++ b/src/calibre/gui2/actions/polish.py
@@ -11,7 +11,7 @@ from collections import OrderedDict
 from functools import partial
 from polyglot.builtins import iteritems, itervalues, map, unicode_type
 
-from PyQt5.Qt import (QDialog, QGridLayout, QIcon, QCheckBox, QLabel, QFrame,
+from qt.core import (QDialog, QGridLayout, QIcon, QCheckBox, QLabel, QFrame,
                       QApplication, QDialogButtonBox, Qt, QSize, QSpacerItem,
                       QSizePolicy, QTimer, QModelIndex, QTextEdit,
                       QInputDialog, QMenu)
diff --git a/src/calibre/gui2/actions/preferences.py b/src/calibre/gui2/actions/preferences.py
index a38f627b37..aa70a16045 100644
--- a/src/calibre/gui2/actions/preferences.py
+++ b/src/calibre/gui2/actions/preferences.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 from functools import partial
 
-from PyQt5.Qt import QIcon, Qt
+from qt.core import QIcon, Qt
 
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.preferences.main import Preferences
diff --git a/src/calibre/gui2/actions/show_book_details.py b/src/calibre/gui2/actions/show_book_details.py
index 8c66d3d88e..0bb041a588 100644
--- a/src/calibre/gui2/actions/show_book_details.py
+++ b/src/calibre/gui2/actions/show_book_details.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import Qt
+from qt.core import Qt
 try:
     from PyQt5 import sip
 except ImportError:
diff --git a/src/calibre/gui2/actions/show_quickview.py b/src/calibre/gui2/actions/show_quickview.py
index fccb8ac1b1..bacda8492e 100644
--- a/src/calibre/gui2/actions/show_quickview.py
+++ b/src/calibre/gui2/actions/show_quickview.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QAction
+from qt.core import QAction
 
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.quickview import Quickview
diff --git a/src/calibre/gui2/actions/show_template_tester.py b/src/calibre/gui2/actions/show_template_tester.py
index a9daf26e62..abe33b3570 100644
--- a/src/calibre/gui2/actions/show_template_tester.py
+++ b/src/calibre/gui2/actions/show_template_tester.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QDialog
+from qt.core import QDialog
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
 from calibre.gui2 import error_dialog
diff --git a/src/calibre/gui2/actions/similar_books.py b/src/calibre/gui2/actions/similar_books.py
index 24ce8942c1..03dad52a32 100644
--- a/src/calibre/gui2/actions/similar_books.py
+++ b/src/calibre/gui2/actions/similar_books.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QToolButton
+from qt.core import QToolButton
 
 from calibre.gui2.actions import InterfaceAction
 from polyglot.builtins import string_or_bytes
diff --git a/src/calibre/gui2/actions/sort.py b/src/calibre/gui2/actions/sort.py
index 7ae1295c2e..f64263ae61 100644
--- a/src/calibre/gui2/actions/sort.py
+++ b/src/calibre/gui2/actions/sort.py
@@ -5,7 +5,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import QToolButton, QAction, pyqtSignal, QIcon
+from qt.core import QToolButton, QAction, pyqtSignal, QIcon
 
 from calibre.gui2.actions import InterfaceAction
 from calibre.utils.icu import sort_key
diff --git a/src/calibre/gui2/actions/store.py b/src/calibre/gui2/actions/store.py
index a10deba24c..0f316160b7 100644
--- a/src/calibre/gui2/actions/store.py
+++ b/src/calibre/gui2/actions/store.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 from functools import partial
 
-from PyQt5.Qt import QIcon, QSize
+from qt.core import QIcon, QSize
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
diff --git a/src/calibre/gui2/actions/tag_mapper.py b/src/calibre/gui2/actions/tag_mapper.py
index bc856dc3a2..dfb8e9c0b8 100644
--- a/src/calibre/gui2/actions/tag_mapper.py
+++ b/src/calibre/gui2/actions/tag_mapper.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import QDialog
+from qt.core import QDialog
 from polyglot.builtins import iteritems, map, range
 
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/actions/toc_edit.py b/src/calibre/gui2/actions/toc_edit.py
index b2d0ccea2e..6da9d49e6c 100644
--- a/src/calibre/gui2/actions/toc_edit.py
+++ b/src/calibre/gui2/actions/toc_edit.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os
 from collections import OrderedDict
 
-from PyQt5.Qt import (QTimer, QDialog, QGridLayout, QCheckBox, QLabel,
+from qt.core import (QTimer, QDialog, QGridLayout, QCheckBox, QLabel,
                       QDialogButtonBox, QIcon)
 
 from calibre.gui2 import error_dialog, gprefs
diff --git a/src/calibre/gui2/actions/tweak_epub.py b/src/calibre/gui2/actions/tweak_epub.py
index 6ca2eff8c3..70bbbc3455 100644
--- a/src/calibre/gui2/actions/tweak_epub.py
+++ b/src/calibre/gui2/actions/tweak_epub.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import time
 
-from PyQt5.Qt import QTimer, QDialog, QDialogButtonBox, QCheckBox, QVBoxLayout, QLabel, Qt
+from qt.core import QTimer, QDialog, QDialogButtonBox, QCheckBox, QVBoxLayout, QLabel, Qt
 
 from calibre.gui2 import error_dialog, question_dialog
 from calibre.gui2.actions import InterfaceAction
diff --git a/src/calibre/gui2/actions/unpack_book.py b/src/calibre/gui2/actions/unpack_book.py
index 4f115b3a95..d8fecea8d6 100644
--- a/src/calibre/gui2/actions/unpack_book.py
+++ b/src/calibre/gui2/actions/unpack_book.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os, weakref, shutil
 
-from PyQt5.Qt import (QDialog, QVBoxLayout, QHBoxLayout, QRadioButton, QFrame,
+from qt.core import (QDialog, QVBoxLayout, QHBoxLayout, QRadioButton, QFrame,
         QPushButton, QLabel, QGroupBox, QGridLayout, QIcon, QSize, QTimer)
 
 from calibre import as_unicode
diff --git a/src/calibre/gui2/actions/view.py b/src/calibre/gui2/actions/view.py
index df402c1481..2f067743a8 100644
--- a/src/calibre/gui2/actions/view.py
+++ b/src/calibre/gui2/actions/view.py
@@ -10,7 +10,7 @@ import json
 import os
 import time
 from functools import partial
-from PyQt5.Qt import QAction, QIcon, Qt, pyqtSignal, QDialog
+from qt.core import QAction, QIcon, Qt, pyqtSignal, QDialog
 
 from calibre.constants import ismacos, iswindows
 from calibre.gui2 import (
diff --git a/src/calibre/gui2/actions/virtual_library.py b/src/calibre/gui2/actions/virtual_library.py
index 08686907bd..6b3dcd67ed 100644
--- a/src/calibre/gui2/actions/virtual_library.py
+++ b/src/calibre/gui2/actions/virtual_library.py
@@ -2,7 +2,7 @@
 # vim:fileencoding=utf-8
 # License: GPLv3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
-from PyQt5.Qt import QToolButton, QAction
+from qt.core import QToolButton, QAction
 
 from calibre.gui2.actions import InterfaceAction
 
diff --git a/src/calibre/gui2/add.py b/src/calibre/gui2/add.py
index df0b9812ab..bad02f007e 100644
--- a/src/calibre/gui2/add.py
+++ b/src/calibre/gui2/add.py
@@ -14,7 +14,7 @@ import traceback
 import weakref
 from collections import OrderedDict
 from io import BytesIO
-from PyQt5.Qt import QObject, Qt, pyqtSignal
+from qt.core import QObject, Qt, pyqtSignal
 from threading import Thread
 
 from calibre import as_unicode, prints
diff --git a/src/calibre/gui2/auto_add.py b/src/calibre/gui2/auto_add.py
index fc119a011d..c78d375773 100644
--- a/src/calibre/gui2/auto_add.py
+++ b/src/calibre/gui2/auto_add.py
@@ -10,7 +10,7 @@ import os, tempfile, shutil, time
 from threading import Thread, Event
 from polyglot.builtins import map
 
-from PyQt5.Qt import (QFileSystemWatcher, QObject, Qt, pyqtSignal, QTimer, QApplication, QCursor)
+from qt.core import (QFileSystemWatcher, QObject, Qt, pyqtSignal, QTimer, QApplication, QCursor)
 
 from calibre import prints
 from calibre.db.adding import filter_filename, compile_rule
diff --git a/src/calibre/gui2/bars.py b/src/calibre/gui2/bars.py
index 362d286d78..3edfb7f115 100644
--- a/src/calibre/gui2/bars.py
+++ b/src/calibre/gui2/bars.py
@@ -7,7 +7,7 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QAction, QMenu, QObject, QToolBar, QToolButton, QSize, pyqtSignal, QKeySequence,
     QTimer, QPropertyAnimation, QEasingCurve, pyqtProperty, QPainter, QWidget, QPalette)
 try:
diff --git a/src/calibre/gui2/book_details.py b/src/calibre/gui2/book_details.py
index 07ed80df11..96770cfccd 100644
--- a/src/calibre/gui2/book_details.py
+++ b/src/calibre/gui2/book_details.py
@@ -7,7 +7,7 @@ import os
 import re
 from collections import namedtuple
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QColor, QEasingCurve, QIcon, QKeySequence, QLayout, QMenu,
     QMimeData, QPainter, QPen, QPixmap, QPropertyAnimation, QRect, QSize, QClipboard,
     QSizePolicy, Qt, QUrl, QWidget, pyqtProperty, pyqtSignal
diff --git a/src/calibre/gui2/catalog/catalog_bibtex.py b/src/calibre/gui2/catalog/catalog_bibtex.py
index dc279c36aa..3f4072999b 100644
--- a/src/calibre/gui2/catalog/catalog_bibtex.py
+++ b/src/calibre/gui2/catalog/catalog_bibtex.py
@@ -7,7 +7,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QWidget, QListWidgetItem
+from qt.core import QWidget, QListWidgetItem
 
 from calibre.gui2 import gprefs
 from calibre.gui2.catalog.catalog_bibtex_ui import Ui_Form
diff --git a/src/calibre/gui2/catalog/catalog_csv_xml.py b/src/calibre/gui2/catalog/catalog_csv_xml.py
index 32cff8e520..9242287143 100644
--- a/src/calibre/gui2/catalog/catalog_csv_xml.py
+++ b/src/calibre/gui2/catalog/catalog_csv_xml.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QWidget, QListWidgetItem, Qt, QVBoxLayout, QLabel, QListWidget, QAbstractItemView
+from qt.core import QWidget, QListWidgetItem, Qt, QVBoxLayout, QLabel, QListWidget, QAbstractItemView
 
 from calibre.constants import ismacos
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/catalog/catalog_epub_mobi.py b/src/calibre/gui2/catalog/catalog_epub_mobi.py
index 7e7be8cd84..9864522f38 100644
--- a/src/calibre/gui2/catalog/catalog_epub_mobi.py
+++ b/src/calibre/gui2/catalog/catalog_epub_mobi.py
@@ -18,7 +18,7 @@ from calibre.utils.localization import localize_user_manual_link
 from polyglot.builtins import native_string_type, unicode_type, zip, range
 
 from .catalog_epub_mobi_ui import Ui_Form
-from PyQt5.Qt import (Qt, QAbstractItemView, QCheckBox, QComboBox,
+from qt.core import (Qt, QAbstractItemView, QCheckBox, QComboBox,
         QDoubleSpinBox, QIcon, QInputDialog, QLineEdit, QRadioButton,
         QSize, QSizePolicy, QTableWidget, QTableWidgetItem, QTextEdit, QToolButton,
         QUrl, QVBoxLayout, QWidget)
diff --git a/src/calibre/gui2/comments_editor.py b/src/calibre/gui2/comments_editor.py
index 8ba6dd9a5f..0325a36826 100644
--- a/src/calibre/gui2/comments_editor.py
+++ b/src/calibre/gui2/comments_editor.py
@@ -11,7 +11,7 @@ from contextlib import contextmanager
 
 from html5_parser import parse
 from lxml import html
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QBrush, QByteArray, QCheckBox, QColor, QColorDialog,
     QDialog, QDialogButtonBox, QFont, QFontInfo, QFontMetrics, QFormLayout,
     QHBoxLayout, QIcon, QKeySequence, QLabel, QLineEdit, QMenu, QPalette,
diff --git a/src/calibre/gui2/complete2.py b/src/calibre/gui2/complete2.py
index f3439e5e2e..3ac2349460 100644
--- a/src/calibre/gui2/complete2.py
+++ b/src/calibre/gui2/complete2.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import (
+from qt.core import (
     QLineEdit, QAbstractListModel, Qt, pyqtSignal, QObject, QKeySequence, QAbstractItemView,
     QApplication, QListView, QPoint, QModelIndex, QEvent,
     QStyleOptionComboBox, QStyle, QComboBox, QTimer)
@@ -519,7 +519,7 @@ class EditWithComplete(EnComboBox):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QDialog, QVBoxLayout
+    from qt.core import QDialog, QVBoxLayout
     from calibre.gui2 import Application
     app = Application([])
     d = QDialog()
diff --git a/src/calibre/gui2/convert/__init__.py b/src/calibre/gui2/convert/__init__.py
index 6c18692df4..f5d35fe092 100644
--- a/src/calibre/gui2/convert/__init__.py
+++ b/src/calibre/gui2/convert/__init__.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import textwrap, codecs, importlib
 from functools import partial
 
-from PyQt5.Qt import (QWidget, QSpinBox, QDoubleSpinBox, QLineEdit, QTextEdit,
+from qt.core import (QWidget, QSpinBox, QDoubleSpinBox, QLineEdit, QTextEdit,
     QCheckBox, QComboBox, Qt, QIcon, pyqtSignal, QLabel, QFontComboBox, QFont,
     QFontInfo, QPlainTextEdit)
 
diff --git a/src/calibre/gui2/convert/bulk.py b/src/calibre/gui2/convert/bulk.py
index 9f9d945e82..775f914c63 100644
--- a/src/calibre/gui2/convert/bulk.py
+++ b/src/calibre/gui2/convert/bulk.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import shutil
 
-from PyQt5.Qt import QModelIndex, QDialog, QApplication, QDialogButtonBox
+from qt.core import QModelIndex, QDialog, QApplication, QDialogButtonBox
 
 from calibre.gui2.convert.single import Config, GroupModel, gprefs
 from calibre.gui2.convert.look_and_feel import LookAndFeelWidget
diff --git a/src/calibre/gui2/convert/docx_output.py b/src/calibre/gui2/convert/docx_output.py
index 932ca92d64..4521de68b3 100644
--- a/src/calibre/gui2/convert/docx_output.py
+++ b/src/calibre/gui2/convert/docx_output.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QFormLayout, QComboBox, QCheckBox, QLineEdit, QDoubleSpinBox, QSizePolicy
+from qt.core import QFormLayout, QComboBox, QCheckBox, QLineEdit, QDoubleSpinBox, QSizePolicy
 
 from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
diff --git a/src/calibre/gui2/convert/font_key.py b/src/calibre/gui2/convert/font_key.py
index d52b77dac7..168a44a709 100644
--- a/src/calibre/gui2/convert/font_key.py
+++ b/src/calibre/gui2/convert/font_key.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QDialog, QDialogButtonBox
+from qt.core import QDialog, QDialogButtonBox
 
 from calibre.gui2.convert.font_key_ui import Ui_Dialog
 from calibre.utils.localization import localize_user_manual_link
@@ -102,7 +102,7 @@ class FontKeyChooser(QDialog, Ui_Dialog):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     d = FontKeyChooser()
     d.exec_()
diff --git a/src/calibre/gui2/convert/heuristics.py b/src/calibre/gui2/convert/heuristics.py
index a053c4655f..93186b2e73 100644
--- a/src/calibre/gui2/convert/heuristics.py
+++ b/src/calibre/gui2/convert/heuristics.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import Qt
+from qt.core import Qt
 
 from calibre.gui2 import gprefs
 from calibre.gui2.convert.heuristics_ui import Ui_Form
diff --git a/src/calibre/gui2/convert/look_and_feel.py b/src/calibre/gui2/convert/look_and_feel.py
index 363a42af89..2237555f6b 100644
--- a/src/calibre/gui2/convert/look_and_feel.py
+++ b/src/calibre/gui2/convert/look_and_feel.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import json
 
-from PyQt5.Qt import Qt, QDialog
+from qt.core import Qt, QDialog
 
 from calibre.gui2.convert.look_and_feel_ui import Ui_Form
 from calibre.gui2.convert import Widget
diff --git a/src/calibre/gui2/convert/metadata.py b/src/calibre/gui2/convert/metadata.py
index 2f31285b51..1567e02f0d 100644
--- a/src/calibre/gui2/convert/metadata.py
+++ b/src/calibre/gui2/convert/metadata.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os, re, errno
 
-from PyQt5.Qt import QPixmap
+from qt.core import QPixmap
 
 from calibre.gui2 import choose_images, error_dialog
 from calibre.gui2.convert.metadata_ui import Ui_Form
diff --git a/src/calibre/gui2/convert/page_setup.py b/src/calibre/gui2/convert/page_setup.py
index 1dcbf70e28..9b5ae4b291 100644
--- a/src/calibre/gui2/convert/page_setup.py
+++ b/src/calibre/gui2/convert/page_setup.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import Qt, QAbstractListModel, QModelIndex, QItemSelectionModel
+from qt.core import Qt, QAbstractListModel, QModelIndex, QItemSelectionModel
 
 from calibre.gui2.convert.page_setup_ui import Ui_Form
 from calibre.gui2.convert import Widget
diff --git a/src/calibre/gui2/convert/pdf_output.py b/src/calibre/gui2/convert/pdf_output.py
index 3bb98534a6..e406372afc 100644
--- a/src/calibre/gui2/convert/pdf_output.py
+++ b/src/calibre/gui2/convert/pdf_output.py
@@ -6,7 +6,7 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QHBoxLayout, QFormLayout, QDoubleSpinBox, QCheckBox, QVBoxLayout
+from qt.core import QHBoxLayout, QFormLayout, QDoubleSpinBox, QCheckBox, QVBoxLayout
 
 from calibre.gui2.convert.pdf_output_ui import Ui_Form
 from calibre.gui2.convert import Widget
diff --git a/src/calibre/gui2/convert/regex_builder.py b/src/calibre/gui2/convert/regex_builder.py
index 4ae1df2860..81af230299 100644
--- a/src/calibre/gui2/convert/regex_builder.py
+++ b/src/calibre/gui2/convert/regex_builder.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from PyQt5.Qt import (QDialog, QWidget, QDialogButtonBox, QApplication,
+from qt.core import (QDialog, QWidget, QDialogButtonBox, QApplication,
         QBrush, QTextCursor, QTextEdit, QByteArray, Qt, pyqtSignal)
 
 from calibre.gui2.convert.regex_builder_ui import Ui_RegexBuilder
diff --git a/src/calibre/gui2/convert/search_and_replace.py b/src/calibre/gui2/convert/search_and_replace.py
index db3e54af1e..cb0a32e5de 100644
--- a/src/calibre/gui2/convert/search_and_replace.py
+++ b/src/calibre/gui2/convert/search_and_replace.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import codecs, json
 
-from PyQt5.Qt import Qt, QTableWidgetItem
+from qt.core import Qt, QTableWidgetItem
 
 from calibre.gui2.convert.search_and_replace_ui import Ui_Form
 from calibre.gui2.convert import Widget
diff --git a/src/calibre/gui2/convert/single.py b/src/calibre/gui2/convert/single.py
index f5ade21cd5..7c6029ac1d 100644
--- a/src/calibre/gui2/convert/single.py
+++ b/src/calibre/gui2/convert/single.py
@@ -5,7 +5,7 @@
 
 import shutil
 
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, QCheckBox, QComboBox, QCoreApplication, QDialog,
     QDialogButtonBox, QFont, QFrame, QGridLayout, QHBoxLayout, QIcon, QLabel,
     QListView, QModelIndex, QScrollArea, QSize, QSizePolicy, QSpacerItem,
diff --git a/src/calibre/gui2/convert/txt_input.py b/src/calibre/gui2/convert/txt_input.py
index f51d6d9745..07d28c1612 100644
--- a/src/calibre/gui2/convert/txt_input.py
+++ b/src/calibre/gui2/convert/txt_input.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QListWidgetItem, Qt
+from qt.core import QListWidgetItem, Qt
 
 from calibre.gui2.convert.txt_input_ui import Ui_Form
 from calibre.gui2.convert import Widget
diff --git a/src/calibre/gui2/convert/xpath_wizard.py b/src/calibre/gui2/convert/xpath_wizard.py
index a0c6e144f7..95bfb403b4 100644
--- a/src/calibre/gui2/convert/xpath_wizard.py
+++ b/src/calibre/gui2/convert/xpath_wizard.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QDialog, QWidget, Qt, QDialogButtonBox, QVBoxLayout
+from qt.core import QDialog, QWidget, Qt, QDialogButtonBox, QVBoxLayout
 
 from calibre.gui2.convert.xpath_wizard_ui import Ui_Form
 from calibre.gui2.convert.xexp_edit_ui import Ui_Form as Ui_Edit
@@ -108,7 +108,7 @@ class XPathEdit(QWidget, Ui_Edit):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     w = XPathEdit()
     w.setObjectName('test')
diff --git a/src/calibre/gui2/cover_flow.py b/src/calibre/gui2/cover_flow.py
index e9c8bd837a..d713dacb26 100644
--- a/src/calibre/gui2/cover_flow.py
+++ b/src/calibre/gui2/cover_flow.py
@@ -11,7 +11,7 @@ Module to implement the Cover Flow feature
 
 import sys, os, time
 
-from PyQt5.Qt import (QImage, QSizePolicy, QTimer, QDialog, Qt, QSize, QAction,
+from qt.core import (QImage, QSizePolicy, QTimer, QDialog, Qt, QSize, QAction,
         QStackedLayout, QLabel, pyqtSignal, QKeySequence, QFont, QApplication, QItemSelectionModel)
 
 from calibre.ebooks.metadata import rating_to_stars
@@ -444,7 +444,7 @@ class CoverFlowMixin(object):
 
 
 def test():
-    from PyQt5.Qt import QMainWindow
+    from qt.core import QMainWindow
     app = QApplication([])
     w = QMainWindow()
     cf = CoverFlow()
@@ -465,7 +465,7 @@ def main(args=sys.argv):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QMainWindow
+    from qt.core import QMainWindow
     app = QApplication([])
     w = QMainWindow()
     cf = CoverFlow()
diff --git a/src/calibre/gui2/covers.py b/src/calibre/gui2/covers.py
index c71d56e70e..b298e4dac2 100644
--- a/src/calibre/gui2/covers.py
+++ b/src/calibre/gui2/covers.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import OrderedDict
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, QHBoxLayout, QTabWidget, QLabel, QSizePolicy, QSize, QFormLayout,
     QSpinBox, pyqtSignal, QPixmap, QDialog, QVBoxLayout, QDialogButtonBox,
     QListWidget, QListWidgetItem, Qt, QGridLayout, QPushButton, QIcon, QApplication,
diff --git a/src/calibre/gui2/css_transform_rules.py b/src/calibre/gui2/css_transform_rules.py
index 6ecb501fba..195977a9e9 100644
--- a/src/calibre/gui2/css_transform_rules.py
+++ b/src/calibre/gui2/css_transform_rules.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, QVBoxLayout, QHBoxLayout, QLabel, QComboBox, QLineEdit,
     QPushButton, QSize, pyqtSignal, QMenu, QDialogButtonBox, QTextCursor
 )
diff --git a/src/calibre/gui2/custom_column_widgets.py b/src/calibre/gui2/custom_column_widgets.py
index fe500125a2..374e0fabdd 100644
--- a/src/calibre/gui2/custom_column_widgets.py
+++ b/src/calibre/gui2/custom_column_widgets.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os
 from functools import partial
 
-from PyQt5.Qt import (Qt, QComboBox, QLabel, QSpinBox, QDoubleSpinBox,
+from qt.core import (Qt, QComboBox, QLabel, QSpinBox, QDoubleSpinBox,
         QDateTime, QGroupBox, QVBoxLayout, QSizePolicy, QGridLayout, QUrl,
         QSpacerItem, QIcon, QCheckBox, QWidget, QHBoxLayout, QLineEdit,
         QMessageBox, QToolButton, QPlainTextEdit, QApplication, QStyle, QDialog)
diff --git a/src/calibre/gui2/dbus_export/demo.py b/src/calibre/gui2/dbus_export/demo.py
index 2f3c0e9ea9..b8274f7b04 100644
--- a/src/calibre/gui2/dbus_export/demo.py
+++ b/src/calibre/gui2/dbus_export/demo.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import time
 
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QMainWindow, QVBoxLayout, Qt, QKeySequence, QAction, QEvent, QStyle,
     QActionGroup, QMenu, QPushButton, QWidget, QTimer, QMessageBox, pyqtSignal)
 
diff --git a/src/calibre/gui2/dbus_export/menu.py b/src/calibre/gui2/dbus_export/menu.py
index f97e3b09b2..91c3ae3606 100644
--- a/src/calibre/gui2/dbus_export/menu.py
+++ b/src/calibre/gui2/dbus_export/menu.py
@@ -9,7 +9,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 # dbus-menu.xml from the libdbusmenu project https://launchpad.net/libdbusmenu
 
 import dbus, sip
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QMenu, QIcon, QKeySequence, QObject, QEvent, QTimer, pyqtSignal, Qt)
 
 from calibre.utils.dbus_service import Object, BusName, method as dbus_method, dbus_property, signal as dbus_signal
diff --git a/src/calibre/gui2/dbus_export/menu2.py b/src/calibre/gui2/dbus_export/menu2.py
index 958e3b0bf5..8b3de3cd0e 100644
--- a/src/calibre/gui2/dbus_export/menu2.py
+++ b/src/calibre/gui2/dbus_export/menu2.py
@@ -13,7 +13,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 # Partial spec: https://wiki.gnome.org/Projects/GLib/GApplication/DBusAPI
 
 import dbus
-from PyQt5.Qt import QObject, pyqtSignal, QTimer, Qt
+from qt.core import QObject, pyqtSignal, QTimer, Qt
 
 from calibre.utils.dbus_service import Object, method as dbus_method, signal as dbus_signal
 from calibre.gui2.dbus_export.utils import set_X_window_properties
diff --git a/src/calibre/gui2/dbus_export/tray.py b/src/calibre/gui2/dbus_export/tray.py
index 1478d93c59..cc19790c08 100644
--- a/src/calibre/gui2/dbus_export/tray.py
+++ b/src/calibre/gui2/dbus_export/tray.py
@@ -14,7 +14,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import os
 
 import dbus
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QObject, pyqtSignal, Qt, QPoint, QRect, QMenu,
     QSystemTrayIcon, QIcon)
 
diff --git a/src/calibre/gui2/dbus_export/utils.py b/src/calibre/gui2/dbus_export/utils.py
index b4dc7c389c..3aeb1eac80 100644
--- a/src/calibre/gui2/dbus_export/utils.py
+++ b/src/calibre/gui2/dbus_export/utils.py
@@ -9,7 +9,7 @@ import sys, array, re, os, errno
 
 import dbus
 
-from PyQt5.Qt import QSize, QImage, Qt, QKeySequence, QBuffer, QByteArray, QIODevice
+from qt.core import QSize, QImage, Qt, QKeySequence, QBuffer, QByteArray, QIODevice
 
 from polyglot.builtins import unicode_type, iteritems
 
diff --git a/src/calibre/gui2/dbus_export/widgets.py b/src/calibre/gui2/dbus_export/widgets.py
index 5e7416a6ef..291467a318 100644
--- a/src/calibre/gui2/dbus_export/widgets.py
+++ b/src/calibre/gui2/dbus_export/widgets.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import time, sys, weakref
 
-from PyQt5.Qt import (
+from qt.core import (
     QObject, QMenuBar, QAction, QEvent, QSystemTrayIcon, QApplication, Qt)
 
 from calibre.constants import iswindows, ismacos
diff --git a/src/calibre/gui2/device.py b/src/calibre/gui2/device.py
index 300fb1db7c..dbd77f927b 100644
--- a/src/calibre/gui2/device.py
+++ b/src/calibre/gui2/device.py
@@ -7,7 +7,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import os, traceback, time, io, re, sys, weakref
 from threading import Thread, Event
 
-from PyQt5.Qt import (
+from qt.core import (
     QMenu, QAction, QActionGroup, QIcon, Qt, pyqtSignal, QDialog,
     QObject, QVBoxLayout, QDialogButtonBox, QCursor, QCoreApplication,
     QApplication, QEventLoop, QTimer)
diff --git a/src/calibre/gui2/device_drivers/configwidget.py b/src/calibre/gui2/device_drivers/configwidget.py
index ab91042450..36d4d28889 100644
--- a/src/calibre/gui2/device_drivers/configwidget.py
+++ b/src/calibre/gui2/device_drivers/configwidget.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from PyQt5.Qt import (QWidget, QListWidgetItem, Qt, QLabel,
+from qt.core import (QWidget, QListWidgetItem, Qt, QLabel,
         QLineEdit, QCheckBox, QComboBox)
 
 from calibre.gui2 import error_dialog, question_dialog
diff --git a/src/calibre/gui2/device_drivers/mtp_config.py b/src/calibre/gui2/device_drivers/mtp_config.py
index a12c9d8526..9a0fc04f8a 100644
--- a/src/calibre/gui2/device_drivers/mtp_config.py
+++ b/src/calibre/gui2/device_drivers/mtp_config.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import weakref
 
-from PyQt5.Qt import (QWidget, QListWidgetItem, Qt, QToolButton, QLabel,
+from qt.core import (QWidget, QListWidgetItem, Qt, QToolButton, QLabel,
         QTabWidget, QGridLayout, QListWidget, QIcon, QLineEdit, QVBoxLayout,
         QPushButton, QGroupBox, QScrollArea, QHBoxLayout, QComboBox,
         pyqtSignal, QSizePolicy, QDialog, QDialogButtonBox, QPlainTextEdit,
diff --git a/src/calibre/gui2/device_drivers/mtp_folder_browser.py b/src/calibre/gui2/device_drivers/mtp_folder_browser.py
index cc6b1f4e68..9a92437b18 100644
--- a/src/calibre/gui2/device_drivers/mtp_folder_browser.py
+++ b/src/calibre/gui2/device_drivers/mtp_folder_browser.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 from operator import attrgetter
 
-from PyQt5.Qt import (QTabWidget, QTreeWidget, QTreeWidgetItem, Qt, QDialog,
+from qt.core import (QTabWidget, QTreeWidget, QTreeWidgetItem, Qt, QDialog,
         QDialogButtonBox, QVBoxLayout, QSize, pyqtSignal, QIcon, QLabel)
 
 from calibre.gui2 import file_icon_provider
diff --git a/src/calibre/gui2/device_drivers/tabbed_device_config.py b/src/calibre/gui2/device_drivers/tabbed_device_config.py
index 7451341c46..433c95a951 100644
--- a/src/calibre/gui2/device_drivers/tabbed_device_config.py
+++ b/src/calibre/gui2/device_drivers/tabbed_device_config.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import weakref, textwrap
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, QLabel, QTabWidget, QGridLayout, QLineEdit, QVBoxLayout,
     QGroupBox, QComboBox, QSizePolicy, QDialog, QDialogButtonBox, QCheckBox,
     QSpacerItem)
diff --git a/src/calibre/gui2/dialogs/add_empty_book.py b/src/calibre/gui2/dialogs/add_empty_book.py
index fa745e6dbd..6323ee1f83 100644
--- a/src/calibre/gui2/dialogs/add_empty_book.py
+++ b/src/calibre/gui2/dialogs/add_empty_book.py
@@ -6,7 +6,7 @@ __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QGridLayout, QLabel, QDialogButtonBox,  QApplication, QSpinBox,
     QToolButton, QIcon, QLineEdit, QComboBox, QCheckBox)
 from calibre.ebooks.metadata import string_to_authors
diff --git a/src/calibre/gui2/dialogs/add_from_isbn.py b/src/calibre/gui2/dialogs/add_from_isbn.py
index 199702d4fd..27021204ba 100644
--- a/src/calibre/gui2/dialogs/add_from_isbn.py
+++ b/src/calibre/gui2/dialogs/add_from_isbn.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QApplication, QIcon, QVBoxLayout, QHBoxLayout, QDialogButtonBox,
     QPlainTextEdit, QPushButton, QLabel, QLineEdit, Qt
 )
diff --git a/src/calibre/gui2/dialogs/authors_edit.py b/src/calibre/gui2/dialogs/authors_edit.py
index 56acced073..c5930023f0 100644
--- a/src/calibre/gui2/dialogs/authors_edit.py
+++ b/src/calibre/gui2/dialogs/authors_edit.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import OrderedDict
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QGridLayout, QDialogButtonBox, QListWidget, QApplication, Qt,
     pyqtSignal, QSize, QPushButton, QIcon, QStyledItemDelegate, QLabel, QAbstractItemView)
 
diff --git a/src/calibre/gui2/dialogs/book_info.py b/src/calibre/gui2/dialogs/book_info.py
index 30e8664849..4818545507 100644
--- a/src/calibre/gui2/dialogs/book_info.py
+++ b/src/calibre/gui2/dialogs/book_info.py
@@ -3,7 +3,7 @@
 
 
 import textwrap
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QBrush, QCheckBox, QCoreApplication, QDialog, QGridLayout,
     QHBoxLayout, QIcon, QKeySequence, QLabel, QListView, QModelIndex, QPalette,
     QPixmap, QPushButton, QShortcut, QSize, QSplitter, Qt, QTimer, QToolButton,
diff --git a/src/calibre/gui2/dialogs/catalog.py b/src/calibre/gui2/dialogs/catalog.py
index aaa6e12d98..781753691b 100644
--- a/src/calibre/gui2/dialogs/catalog.py
+++ b/src/calibre/gui2/dialogs/catalog.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os, sys, importlib, weakref
 
-from PyQt5.Qt import QDialog, QCoreApplication, QSize, QScrollArea, QApplication, QDialogButtonBox
+from qt.core import QDialog, QCoreApplication, QSize, QScrollArea, QApplication, QDialogButtonBox
 
 from calibre.customize.ui import config
 from calibre.gui2.dialogs.catalog_ui import Ui_Dialog
@@ -218,7 +218,7 @@ class Catalog(QDialog, Ui_Dialog):
         To add help functionality for a specific format:
         In gui2.catalog.catalog_<format>.py, add the following:
             from calibre.gui2 import open_url
-            from PyQt5.Qt import QUrl
+            from qt.core import QUrl
 
         In the PluginWidget() class, add this method:
             def show_help(self):
diff --git a/src/calibre/gui2/dialogs/check_library.py b/src/calibre/gui2/dialogs/check_library.py
index d5fe06cf3e..cedab3b645 100644
--- a/src/calibre/gui2/dialogs/check_library.py
+++ b/src/calibre/gui2/dialogs/check_library.py
@@ -8,7 +8,7 @@ __license__   = 'GPL v3'
 import os
 from threading import Thread
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QVBoxLayout, QHBoxLayout, QTreeWidget, QLabel, QPushButton,
     QApplication, QTreeWidgetItem, QLineEdit, Qt, QSize,
     QTimer, QIcon, QTextEdit, QSplitter, QWidget, QGridLayout, pyqtSignal)
diff --git a/src/calibre/gui2/dialogs/choose_format.py b/src/calibre/gui2/dialogs/choose_format.py
index d8390e8114..caa984ea0b 100644
--- a/src/calibre/gui2/dialogs/choose_format.py
+++ b/src/calibre/gui2/dialogs/choose_format.py
@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QListWidgetItem, QModelIndex, QIcon, QLabel, QVBoxLayout, QSize,
     QDialogButtonBox, QListWidget, QHBoxLayout, QPushButton, QMenu)
 
diff --git a/src/calibre/gui2/dialogs/choose_format_device.py b/src/calibre/gui2/dialogs/choose_format_device.py
index 132df5f37b..a0b586b465 100644
--- a/src/calibre/gui2/dialogs/choose_format_device.py
+++ b/src/calibre/gui2/dialogs/choose_format_device.py
@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 
-from PyQt5.Qt import QDialog, QTreeWidgetItem, QIcon, QModelIndex
+from qt.core import QDialog, QTreeWidgetItem, QIcon, QModelIndex
 
 from calibre.gui2 import file_icon_provider
 from calibre.gui2.dialogs.choose_format_device_ui import Ui_ChooseFormatDeviceDialog
diff --git a/src/calibre/gui2/dialogs/choose_library.py b/src/calibre/gui2/dialogs/choose_library.py
index 45b1156749..e5e10a8095 100644
--- a/src/calibre/gui2/dialogs/choose_library.py
+++ b/src/calibre/gui2/dialogs/choose_library.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os, errno
 from threading import Thread, Event
 
-from PyQt5.Qt import QDialog, QTimer, Qt, pyqtSignal
+from qt.core import QDialog, QTimer, Qt, pyqtSignal
 
 from calibre.gui2.dialogs.choose_library_ui import Ui_Dialog
 from calibre.gui2.dialogs.progress import ProgressDialog as PD
diff --git a/src/calibre/gui2/dialogs/choose_plugin_toolbars.py b/src/calibre/gui2/dialogs/choose_plugin_toolbars.py
index ddb24b9213..27c88f30c7 100644
--- a/src/calibre/gui2/dialogs/choose_plugin_toolbars.py
+++ b/src/calibre/gui2/dialogs/choose_plugin_toolbars.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
 
-from PyQt5.Qt import (QDialog, QVBoxLayout, QLabel, QDialogButtonBox,
+from qt.core import (QDialog, QVBoxLayout, QLabel, QDialogButtonBox,
             QListWidget, QAbstractItemView, QSizePolicy)
 
 
diff --git a/src/calibre/gui2/dialogs/comments_dialog.py b/src/calibre/gui2/dialogs/comments_dialog.py
index ae284cfa70..b766ee2a7c 100644
--- a/src/calibre/gui2/dialogs/comments_dialog.py
+++ b/src/calibre/gui2/dialogs/comments_dialog.py
@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
-from PyQt5.Qt import Qt, QDialog, QDialogButtonBox, QVBoxLayout, QPlainTextEdit, QSize, QApplication
+from qt.core import Qt, QDialog, QDialogButtonBox, QVBoxLayout, QPlainTextEdit, QSize, QApplication
 
 from calibre.gui2 import gprefs, Application
 from calibre.gui2.dialogs.comments_dialog_ui import Ui_CommentsDialog
diff --git a/src/calibre/gui2/dialogs/confirm_delete.py b/src/calibre/gui2/dialogs/confirm_delete.py
index 5e26c12cac..46e5b59f19 100644
--- a/src/calibre/gui2/dialogs/confirm_delete.py
+++ b/src/calibre/gui2/dialogs/confirm_delete.py
@@ -5,7 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, Qt, QIcon, QVBoxLayout, QHBoxLayout, QLabel, QCheckBox, QDialogButtonBox
 )
 
diff --git a/src/calibre/gui2/dialogs/confirm_delete_location.py b/src/calibre/gui2/dialogs/confirm_delete_location.py
index bb79ce1a03..a649a47fa7 100644
--- a/src/calibre/gui2/dialogs/confirm_delete_location.py
+++ b/src/calibre/gui2/dialogs/confirm_delete_location.py
@@ -7,7 +7,7 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net' \
 __docformat__ = 'restructuredtext en'
 
 from calibre.gui2.dialogs.confirm_delete_location_ui import Ui_Dialog
-from PyQt5.Qt import QDialog, Qt, QPixmap, QIcon
+from qt.core import QDialog, Qt, QPixmap, QIcon
 
 
 class Dialog(QDialog, Ui_Dialog):
diff --git a/src/calibre/gui2/dialogs/confirm_merge.py b/src/calibre/gui2/dialogs/confirm_merge.py
index c6cf0657ea..3fb40b67ef 100644
--- a/src/calibre/gui2/dialogs/confirm_merge.py
+++ b/src/calibre/gui2/dialogs/confirm_merge.py
@@ -5,7 +5,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import (
+from qt.core import (
     QVBoxLayout, QSplitter, QWidget, QLabel, QCheckBox, QTextBrowser, Qt, QDialog, QDialogButtonBox
 )
 
diff --git a/src/calibre/gui2/dialogs/conversion_error.py b/src/calibre/gui2/dialogs/conversion_error.py
index 2bf85113a2..17e91ec8ad 100644
--- a/src/calibre/gui2/dialogs/conversion_error.py
+++ b/src/calibre/gui2/dialogs/conversion_error.py
@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import QDialog
+from qt.core import QDialog
 
 from calibre.gui2.dialogs.conversion_error_ui import Ui_ConversionErrorDialog
 
diff --git a/src/calibre/gui2/dialogs/custom_recipes.py b/src/calibre/gui2/dialogs/custom_recipes.py
index b0009ecd6f..ba9bc2ddab 100644
--- a/src/calibre/gui2/dialogs/custom_recipes.py
+++ b/src/calibre/gui2/dialogs/custom_recipes.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os, re, textwrap, time
 
-from PyQt5.Qt import (
+from qt.core import (
     QVBoxLayout, QStackedWidget, QSize, QPushButton, QIcon, QWidget, QListView, QItemSelectionModel,
     QHBoxLayout, QAbstractListModel, Qt, QLabel, QSizePolicy, pyqtSignal, QSortFilterProxyModel,
     QFormLayout, QSpinBox, QLineEdit, QGroupBox, QListWidget, QListWidgetItem,
diff --git a/src/calibre/gui2/dialogs/delete_matching_from_device.py b/src/calibre/gui2/dialogs/delete_matching_from_device.py
index 4ecf86e8c7..672bf6ce75 100644
--- a/src/calibre/gui2/dialogs/delete_matching_from_device.py
+++ b/src/calibre/gui2/dialogs/delete_matching_from_device.py
@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
-from PyQt5.Qt import Qt, QDialog, QTableWidgetItem, QAbstractItemView
+from qt.core import Qt, QDialog, QTableWidgetItem, QAbstractItemView
 
 from calibre import strftime
 from calibre.ebooks.metadata import authors_to_string, authors_to_sort_string, \
diff --git a/src/calibre/gui2/dialogs/device_category_editor.py b/src/calibre/gui2/dialogs/device_category_editor.py
index 1ed833b6be..717083f834 100644
--- a/src/calibre/gui2/dialogs/device_category_editor.py
+++ b/src/calibre/gui2/dialogs/device_category_editor.py
@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import Qt, QDialog, QListWidgetItem
+from qt.core import Qt, QDialog, QListWidgetItem
 
 from calibre.gui2.dialogs.device_category_editor_ui import Ui_DeviceCategoryEditor
 from calibre.gui2 import question_dialog, error_dialog
diff --git a/src/calibre/gui2/dialogs/drm_error.py b/src/calibre/gui2/dialogs/drm_error.py
index ba5d45c7eb..3377cf67f6 100644
--- a/src/calibre/gui2/dialogs/drm_error.py
+++ b/src/calibre/gui2/dialogs/drm_error.py
@@ -7,7 +7,7 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QDialog
+from qt.core import QDialog
 from calibre.gui2.dialogs.drm_error_ui import Ui_Dialog
 from polyglot.builtins import unicode_type
 
diff --git a/src/calibre/gui2/dialogs/duplicates.py b/src/calibre/gui2/dialogs/duplicates.py
index 3cbb6e55b2..e21bb6fb7c 100644
--- a/src/calibre/gui2/dialogs/duplicates.py
+++ b/src/calibre/gui2/dialogs/duplicates.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os.path
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QGridLayout, QIcon, QLabel, QTreeWidget, QTreeWidgetItem, Qt,
     QFont, QDialogButtonBox, QApplication)
 
diff --git a/src/calibre/gui2/dialogs/edit_authors_dialog.py b/src/calibre/gui2/dialogs/edit_authors_dialog.py
index e145756b52..73ad303410 100644
--- a/src/calibre/gui2/dialogs/edit_authors_dialog.py
+++ b/src/calibre/gui2/dialogs/edit_authors_dialog.py
@@ -7,7 +7,7 @@ __license__   = 'GPL v3'
 
 from functools import partial
 
-from PyQt5.Qt import (Qt, QDialog, QTableWidgetItem, QAbstractItemView, QIcon,
+from qt.core import (Qt, QDialog, QTableWidgetItem, QAbstractItemView, QIcon,
                   QDialogButtonBox, QFrame, QLabel, QTimer, QMenu, QApplication,
                   QByteArray, QItemDelegate, QAction)
 
diff --git a/src/calibre/gui2/dialogs/enum_values_edit.py b/src/calibre/gui2/dialogs/enum_values_edit.py
index 80b98cf282..682ffebb31 100644
--- a/src/calibre/gui2/dialogs/enum_values_edit.py
+++ b/src/calibre/gui2/dialogs/enum_values_edit.py
@@ -2,7 +2,7 @@
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
 # License: GPLv3 Copyright: 2020, Charles Haley
 
-from PyQt5.Qt import (QDialog, QColor, QDialogButtonBox, QHeaderView,
+from qt.core import (QDialog, QColor, QDialogButtonBox, QHeaderView,
                       QApplication, QGridLayout, QTableWidget,
                       QTableWidgetItem, QVBoxLayout, QToolButton, QIcon,
                       QAbstractItemView, QComboBox)
diff --git a/src/calibre/gui2/dialogs/exim.py b/src/calibre/gui2/dialogs/exim.py
index 69d05c240b..8142e34b94 100644
--- a/src/calibre/gui2/dialogs/exim.py
+++ b/src/calibre/gui2/dialogs/exim.py
@@ -7,7 +7,7 @@ from functools import partial
 from threading import Thread, Event
 import os, stat
 
-from PyQt5.Qt import (
+from qt.core import (
     QSize, QStackedLayout, QWidget, QVBoxLayout, QLabel, QPushButton,
     QListWidget, QListWidgetItem, QIcon, Qt, pyqtSignal, QGridLayout,
     QProgressBar, QDialog, QDialogButtonBox, QScrollArea, QLineEdit, QFrame, QAbstractItemView
diff --git a/src/calibre/gui2/dialogs/match_books.py b/src/calibre/gui2/dialogs/match_books.py
index 7801c7f931..a6c8b42c08 100644
--- a/src/calibre/gui2/dialogs/match_books.py
+++ b/src/calibre/gui2/dialogs/match_books.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import (Qt, QDialog, QAbstractItemView, QTableWidgetItem,
+from qt.core import (Qt, QDialog, QAbstractItemView, QTableWidgetItem,
                       QByteArray, QApplication, QCursor)
 
 from calibre.gui2 import gprefs, error_dialog
diff --git a/src/calibre/gui2/dialogs/message_box.py b/src/calibre/gui2/dialogs/message_box.py
index 52c5e5c29d..c1c3817082 100644
--- a/src/calibre/gui2/dialogs/message_box.py
+++ b/src/calibre/gui2/dialogs/message_box.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import sys
 
-from PyQt5.Qt import (
+from qt.core import (
     QPainter, QDialog, QIcon, QApplication, QSize, QKeySequence,
     QAction, Qt, QTextBrowser, QDialogButtonBox, QVBoxLayout, QGridLayout,
     QLabel, QPlainTextEdit, QTextDocument, QCheckBox, pyqtSignal, QWidget,
diff --git a/src/calibre/gui2/dialogs/metadata_bulk.py b/src/calibre/gui2/dialogs/metadata_bulk.py
index d127ab989e..3fd5ba0d3e 100644
--- a/src/calibre/gui2/dialogs/metadata_bulk.py
+++ b/src/calibre/gui2/dialogs/metadata_bulk.py
@@ -7,7 +7,7 @@ import numbers
 import regex
 from collections import defaultdict, namedtuple
 from io import BytesIO
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QComboBox, QCompleter, QCoreApplication, QDateTime, QDialog,
     QDialogButtonBox, QFont, QGridLayout, QInputDialog, QLabel, QLineEdit,
     QProgressBar, QSize, Qt, QVBoxLayout, pyqtSignal
diff --git a/src/calibre/gui2/dialogs/opml.py b/src/calibre/gui2/dialogs/opml.py
index ccb810c760..23996fbc90 100644
--- a/src/calibre/gui2/dialogs/opml.py
+++ b/src/calibre/gui2/dialogs/opml.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from collections import defaultdict, namedtuple
 from operator import itemgetter
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QFormLayout, QHBoxLayout, QLineEdit, QToolButton, QIcon,
     QDialogButtonBox, Qt, QSpinBox, QCheckBox)
 
diff --git a/src/calibre/gui2/dialogs/password.py b/src/calibre/gui2/dialogs/password.py
index 91faf12c64..134ec669cf 100644
--- a/src/calibre/gui2/dialogs/password.py
+++ b/src/calibre/gui2/dialogs/password.py
@@ -4,7 +4,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
-from PyQt5.Qt import QDialog, QLineEdit, Qt
+from qt.core import QDialog, QLineEdit, Qt
 
 from calibre.gui2.dialogs.password_ui import Ui_Dialog
 from calibre.gui2 import dynamic
diff --git a/src/calibre/gui2/dialogs/plugin_updater.py b/src/calibre/gui2/dialogs/plugin_updater.py
index e870574d9d..9f6ea864c7 100644
--- a/src/calibre/gui2/dialogs/plugin_updater.py
+++ b/src/calibre/gui2/dialogs/plugin_updater.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import datetime
 import re
 import traceback
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemView, QAbstractTableModel, QAction, QApplication, QBrush, QComboBox,
     QDialog, QDialogButtonBox, QFont, QFrame, QHBoxLayout, QIcon, QLabel, QLineEdit,
     QModelIndex, QPixmap, QSize, QSortFilterProxyModel, Qt, QTableView, QUrl,
diff --git a/src/calibre/gui2/dialogs/progress.py b/src/calibre/gui2/dialogs/progress.py
index f466dba55b..778795336c 100644
--- a/src/calibre/gui2/dialogs/progress.py
+++ b/src/calibre/gui2/dialogs/progress.py
@@ -5,7 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, pyqtSignal, Qt, QVBoxLayout, QLabel, QFont, QProgressBar, QSize,
     QDialogButtonBox, QApplication, QFontMetrics, QHBoxLayout, QIcon)
 
@@ -168,7 +168,7 @@ class BlockingBusy(QDialog):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QTimer
+    from qt.core import QTimer
     app = QApplication([])
     d = ProgressDialog('A title', 'A message', icon='lt.png')
     d.show(), d.canceled_signal.connect(app.quit)
diff --git a/src/calibre/gui2/dialogs/quickview.py b/src/calibre/gui2/dialogs/quickview.py
index 255a844468..be0f2bed27 100644
--- a/src/calibre/gui2/dialogs/quickview.py
+++ b/src/calibre/gui2/dialogs/quickview.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import traceback
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QDialog, QAbstractItemView, QTableWidgetItem, QIcon, QListWidgetItem,
     QCoreApplication, QEvent, QObject, QApplication, pyqtSignal, QByteArray, QMenu,
     QShortcut)
diff --git a/src/calibre/gui2/dialogs/restore_library.py b/src/calibre/gui2/dialogs/restore_library.py
index 71fde86e16..da45de141b 100644
--- a/src/calibre/gui2/dialogs/restore_library.py
+++ b/src/calibre/gui2/dialogs/restore_library.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2011, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import (QDialog, QLabel, QVBoxLayout, QDialogButtonBox,
+from qt.core import (QDialog, QLabel, QVBoxLayout, QDialogButtonBox,
         QProgressBar, QSize, QTimer, pyqtSignal, Qt)
 
 from calibre.gui2 import (error_dialog, question_dialog, warning_dialog,
diff --git a/src/calibre/gui2/dialogs/saved_search_editor.py b/src/calibre/gui2/dialogs/saved_search_editor.py
index 8f1fa84e18..3229dda830 100644
--- a/src/calibre/gui2/dialogs/saved_search_editor.py
+++ b/src/calibre/gui2/dialogs/saved_search_editor.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2008, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QFormLayout, QIcon, QLabel, QLineEdit, QListWidget, Qt, QVBoxLayout, QDialog,
     QDialogButtonBox, QPlainTextEdit
 )
diff --git a/src/calibre/gui2/dialogs/scheduler.py b/src/calibre/gui2/dialogs/scheduler.py
index 29a3f48d30..c11c087a0a 100644
--- a/src/calibre/gui2/dialogs/scheduler.py
+++ b/src/calibre/gui2/dialogs/scheduler.py
@@ -12,7 +12,7 @@ from datetime import timedelta
 import calendar, textwrap
 from collections import OrderedDict
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, Qt, QTime, QObject, QMenu, QHBoxLayout, QAction, QIcon, QMutex, QApplication,
     QTimer, pyqtSignal, QWidget, QGridLayout, QCheckBox, QTimeEdit, QLabel,
     QLineEdit, QDoubleSpinBox, QSize, QTreeView, QSizePolicy, QToolButton,
diff --git a/src/calibre/gui2/dialogs/search.py b/src/calibre/gui2/dialogs/search.py
index 3e85e2ef34..d02f14dede 100644
--- a/src/calibre/gui2/dialogs/search.py
+++ b/src/calibre/gui2/dialogs/search.py
@@ -6,7 +6,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import re, copy
 from datetime import date
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QDialogButtonBox, QFrame, QLabel, QComboBox, QIcon, QVBoxLayout, Qt,
     QSize, QHBoxLayout, QTabWidget, QLineEdit, QWidget, QGroupBox, QFormLayout,
     QSpinBox, QRadioButton
diff --git a/src/calibre/gui2/dialogs/select_formats.py b/src/calibre/gui2/dialogs/select_formats.py
index 8c5571903d..f28b90eb29 100644
--- a/src/calibre/gui2/dialogs/select_formats.py
+++ b/src/calibre/gui2/dialogs/select_formats.py
@@ -7,7 +7,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QVBoxLayout, QDialog, QLabel, QDialogButtonBox, Qt, \
+from qt.core import QVBoxLayout, QDialog, QLabel, QDialogButtonBox, Qt, \
         QAbstractListModel, QListView, QSize, QApplication, QAbstractItemView
 
 from calibre.gui2 import file_icon_provider
diff --git a/src/calibre/gui2/dialogs/smartdevice.py b/src/calibre/gui2/dialogs/smartdevice.py
index b28c467e5d..6dc518f055 100644
--- a/src/calibre/gui2/dialogs/smartdevice.py
+++ b/src/calibre/gui2/dialogs/smartdevice.py
@@ -4,7 +4,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import (QDialog, QLineEdit, Qt)
+from qt.core import (QDialog, QLineEdit, Qt)
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.dialogs.smartdevice_ui import Ui_Dialog
diff --git a/src/calibre/gui2/dialogs/tag_categories.py b/src/calibre/gui2/dialogs/tag_categories.py
index 4e209d1bd8..cb1d06be02 100644
--- a/src/calibre/gui2/dialogs/tag_categories.py
+++ b/src/calibre/gui2/dialogs/tag_categories.py
@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QDialog, QIcon, QListWidgetItem)
 
 from calibre.gui2.dialogs.tag_categories_ui import Ui_TagCategories
diff --git a/src/calibre/gui2/dialogs/tag_editor.py b/src/calibre/gui2/dialogs/tag_editor.py
index 653f7a9e77..e36df92a74 100644
--- a/src/calibre/gui2/dialogs/tag_editor.py
+++ b/src/calibre/gui2/dialogs/tag_editor.py
@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import Qt, QDialog, QAbstractItemView, QApplication
+from qt.core import Qt, QDialog, QAbstractItemView, QApplication
 
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.dialogs.tag_editor_ui import Ui_TagEditor
diff --git a/src/calibre/gui2/dialogs/tag_list_editor.py b/src/calibre/gui2/dialogs/tag_list_editor.py
index 8e6a10ee00..85449e0410 100644
--- a/src/calibre/gui2/dialogs/tag_list_editor.py
+++ b/src/calibre/gui2/dialogs/tag_list_editor.py
@@ -5,7 +5,7 @@
 
 from functools import partial
 
-from PyQt5.Qt import (Qt, QDialog, QTableWidgetItem, QIcon, QByteArray, QSize, QAbstractItemView,
+from qt.core import (Qt, QDialog, QTableWidgetItem, QIcon, QByteArray, QSize, QAbstractItemView,
                       QDialogButtonBox, QItemDelegate, QApplication,
                       pyqtSignal, QAction, QFrame, QLabel, QTimer, QMenu, QColor)
 
diff --git a/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py b/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py
index f894dfa7e6..417641e127 100644
--- a/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py
+++ b/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2008, Kovid Goyal <kovid at kovidgoyal.net>
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-from PyQt5.Qt import (Qt, QTableWidget, pyqtSignal)
+from qt.core import (Qt, QTableWidget, pyqtSignal)
 
 
 class TleTableWidget(QTableWidget):
diff --git a/src/calibre/gui2/dialogs/template_dialog.py b/src/calibre/gui2/dialogs/template_dialog.py
index 37dc097d07..217dc8bdd9 100644
--- a/src/calibre/gui2/dialogs/template_dialog.py
+++ b/src/calibre/gui2/dialogs/template_dialog.py
@@ -7,7 +7,7 @@ __license__   = 'GPL v3'
 
 import json, os, traceback
 
-from PyQt5.Qt import (Qt, QDialog, QDialogButtonBox, QSyntaxHighlighter, QFont,
+from qt.core import (Qt, QDialog, QDialogButtonBox, QSyntaxHighlighter, QFont,
                       QRegExp, QApplication, QTextCharFormat, QColor, QCursor,
                       QIcon, QSize, QPalette)
 
diff --git a/src/calibre/gui2/dialogs/template_dialog_box_layout.py b/src/calibre/gui2/dialogs/template_dialog_box_layout.py
index 5ac5358b82..91061ead42 100644
--- a/src/calibre/gui2/dialogs/template_dialog_box_layout.py
+++ b/src/calibre/gui2/dialogs/template_dialog_box_layout.py
@@ -4,7 +4,7 @@ Created on 20 Jan 2021
 @author: Charles Haley
 '''
 
-from PyQt5.Qt import (QBoxLayout)
+from qt.core import (QBoxLayout)
 
 
 class BoxLayout(QBoxLayout):
diff --git a/src/calibre/gui2/dialogs/template_line_editor.py b/src/calibre/gui2/dialogs/template_line_editor.py
index 873d45dc05..b735e5e6d4 100644
--- a/src/calibre/gui2/dialogs/template_line_editor.py
+++ b/src/calibre/gui2/dialogs/template_line_editor.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QLineEdit
+from qt.core import QLineEdit
 
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
 
diff --git a/src/calibre/gui2/dialogs/trim_image.py b/src/calibre/gui2/dialogs/trim_image.py
index 989adf3c89..47664bba63 100644
--- a/src/calibre/gui2/dialogs/trim_image.py
+++ b/src/calibre/gui2/dialogs/trim_image.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys, os
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QGridLayout, QToolBar, Qt, QLabel, QIcon, QDialogButtonBox, QSize,
     QApplication, QKeySequence)
 
diff --git a/src/calibre/gui2/dnd.py b/src/calibre/gui2/dnd.py
index ae7178cb15..4e2e7235fe 100644
--- a/src/calibre/gui2/dnd.py
+++ b/src/calibre/gui2/dnd.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os
 import posixpath
 import re
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QDialogButtonBox, QImageReader, QLabel, QPixmap, QProgressBar, Qt,
     QTimer, QUrl, QVBoxLayout
 )
diff --git a/src/calibre/gui2/email.py b/src/calibre/gui2/email.py
index 367723d435..4a8a7e57cf 100644
--- a/src/calibre/gui2/email.py
+++ b/src/calibre/gui2/email.py
@@ -12,7 +12,7 @@ from threading import Thread
 from itertools import repeat
 from collections import defaultdict
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QDialog, QGridLayout, QIcon, QListWidget, QDialogButtonBox,
     QListWidgetItem, QLabel, QLineEdit, QPushButton)
 
@@ -504,6 +504,6 @@ class EmailMixin(object):  # {{{
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])  # noqa
     print(select_recipients())
diff --git a/src/calibre/gui2/font_family_chooser.py b/src/calibre/gui2/font_family_chooser.py
index 060933a651..9b2b00fdf1 100644
--- a/src/calibre/gui2/font_family_chooser.py
+++ b/src/calibre/gui2/font_family_chooser.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os, shutil
 
-from PyQt5.Qt import (QFontInfo, QFontMetrics, Qt, QFont, QFontDatabase, QPen,
+from qt.core import (QFontInfo, QFontMetrics, Qt, QFont, QFontDatabase, QPen,
         QStyledItemDelegate, QSize, QStyle, QStringListModel, pyqtSignal,
         QDialog, QVBoxLayout, QApplication, QFontComboBox, QPushButton,
         QToolButton, QGridLayout, QListView, QWidget, QDialogButtonBox, QIcon,
diff --git a/src/calibre/gui2/gestures.py b/src/calibre/gui2/gestures.py
index cdf9d92c58..fc2c670f9b 100644
--- a/src/calibre/gui2/gestures.py
+++ b/src/calibre/gui2/gestures.py
@@ -5,7 +5,7 @@
 
 import sys, os
 
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QEvent, QMouseEvent, QObject, QPointF, QScroller, Qt, QTouchDevice,
     pyqtSignal
 )
diff --git a/src/calibre/gui2/icon_theme.py b/src/calibre/gui2/icon_theme.py
index edd469fb4f..ca6790f14c 100644
--- a/src/calibre/gui2/icon_theme.py
+++ b/src/calibre/gui2/icon_theme.py
@@ -11,7 +11,7 @@ from io import BytesIO
 from threading import Thread, Event
 from multiprocessing.pool import ThreadPool
 
-from PyQt5.Qt import (
+from qt.core import (
     QImageReader, QFormLayout, QVBoxLayout, QSplitter, QGroupBox, QListWidget,
     QLineEdit, QSpinBox, QTextEdit, QSize, QListWidgetItem, QIcon, QImage,
     pyqtSignal, QStackedLayout, QWidget, QLabel, Qt, QComboBox, QPixmap, QDialog,
diff --git a/src/calibre/gui2/image_popup.py b/src/calibre/gui2/image_popup.py
index fc6288e549..b88e331087 100644
--- a/src/calibre/gui2/image_popup.py
+++ b/src/calibre/gui2/image_popup.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import (QDialog, QPixmap, QUrl, QScrollArea, QLabel, QSizePolicy,
+from qt.core import (QDialog, QPixmap, QUrl, QScrollArea, QLabel, QSizePolicy,
         QDialogButtonBox, QVBoxLayout, QPalette, QApplication, QSize, QIcon,
         Qt, QTransform, QSvgRenderer, QImage, QPainter, QHBoxLayout, QCheckBox)
 
diff --git a/src/calibre/gui2/init.py b/src/calibre/gui2/init.py
index da896718f7..e800e6f794 100644
--- a/src/calibre/gui2/init.py
+++ b/src/calibre/gui2/init.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import functools
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QIcon, QLabel, QMenu, QPainter, QSizePolicy, QSplitter,
     QStackedWidget, QStatusBar, QStyle, QStyleOption, Qt, QTabBar, QTimer,
     QToolButton, QVBoxLayout, QWidget, QDialog, QEvent
diff --git a/src/calibre/gui2/job_indicator.py b/src/calibre/gui2/job_indicator.py
index b568d72e82..7181f968c1 100644
--- a/src/calibre/gui2/job_indicator.py
+++ b/src/calibre/gui2/job_indicator.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractAnimation, QBrush, QColor, QEasingCurve, QPainter, QPainterPath,
     QPalette, QPoint, QPointF, QPropertyAnimation, QRect, Qt, QWidget
 )
diff --git a/src/calibre/gui2/jobs.py b/src/calibre/gui2/jobs.py
index 0d256dc310..1e2fd93e35 100644
--- a/src/calibre/gui2/jobs.py
+++ b/src/calibre/gui2/jobs.py
@@ -11,7 +11,7 @@ Job management.
 
 import time
 
-from PyQt5.Qt import (QAbstractTableModel, QModelIndex, Qt, QPainter,
+from qt.core import (QAbstractTableModel, QModelIndex, Qt, QPainter,
     QTimer, pyqtSignal, QIcon, QDialog, QAbstractItemDelegate, QApplication, QEvent,
     QSize, QStyleOptionProgressBar, QStyle, QToolTip, QWidget, QStyleOption,
     QHBoxLayout, QVBoxLayout, QSizePolicy, QLabel, QCoreApplication, QAction, QItemSelectionModel,
diff --git a/src/calibre/gui2/keyboard.py b/src/calibre/gui2/keyboard.py
index 2f5eb97a9a..e422bd0009 100644
--- a/src/calibre/gui2/keyboard.py
+++ b/src/calibre/gui2/keyboard.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 from collections import OrderedDict
 from functools import partial
 
-from PyQt5.Qt import (QObject, QKeySequence, QAbstractItemModel, QModelIndex, QItemSelectionModel,
+from qt.core import (QObject, QKeySequence, QAbstractItemModel, QModelIndex, QItemSelectionModel,
         Qt, QStyledItemDelegate, QTextDocument, QStyle, pyqtSignal, QFrame, QAbstractItemView,
         QApplication, QSize, QRectF, QWidget, QTreeView, QHBoxLayout, QVBoxLayout, QAbstractItemDelegate,
         QGridLayout, QLabel, QRadioButton, QPushButton, QToolButton, QIcon, QEvent)
diff --git a/src/calibre/gui2/languages.py b/src/calibre/gui2/languages.py
index e49dce1c86..9a878b4149 100644
--- a/src/calibre/gui2/languages.py
+++ b/src/calibre/gui2/languages.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QComboBox
+from qt.core import QComboBox
 from calibre.gui2 import gui_prefs
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.utils.localization import lang_map_for_ui
diff --git a/src/calibre/gui2/layout.py b/src/calibre/gui2/layout.py
index ea2b9c9203..f832c0e919 100644
--- a/src/calibre/gui2/layout.py
+++ b/src/calibre/gui2/layout.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QActionGroup, QCoreApplication, QFrame, QHBoxLayout, QIcon, QLabel, QLineEdit,
     QMenu, QObject, QSizePolicy, Qt, QToolButton, QVBoxLayout, QWidget, pyqtSignal
 )
diff --git a/src/calibre/gui2/layout_menu.py b/src/calibre/gui2/layout_menu.py
index 5096cd84c1..2d24ad71ce 100644
--- a/src/calibre/gui2/layout_menu.py
+++ b/src/calibre/gui2/layout_menu.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QFontMetrics, QHBoxLayout, QIcon, QMenu, QPainter, QPushButton, QSize,
     QSizePolicy, Qt, QWidget, QStyleOption, QStyle, QEvent)
 
diff --git a/src/calibre/gui2/library/alternate_views.py b/src/calibre/gui2/library/alternate_views.py
index 89e76025e4..dc94eb7623 100644
--- a/src/calibre/gui2/library/alternate_views.py
+++ b/src/calibre/gui2/library/alternate_views.py
@@ -10,7 +10,7 @@ import math
 import operator
 import os
 from functools import wraps
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemView, QApplication, QBuffer, QByteArray, QColor, QDrag,
     QEasingCurve, QEvent, QFont, QHelpEvent, QIcon, QImage, QItemSelection,
     QItemSelectionModel, QListView, QMimeData, QModelIndex, QPainter, QPixmap,
diff --git a/src/calibre/gui2/library/annotations.py b/src/calibre/gui2/library/annotations.py
index 8da1df5ed8..1c8291ffd2 100644
--- a/src/calibre/gui2/library/annotations.py
+++ b/src/calibre/gui2/library/annotations.py
@@ -6,7 +6,7 @@ import codecs
 import json
 import os
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemView, QApplication, QCheckBox, QComboBox, QCursor, QDateTime,
     QDialog, QDialogButtonBox, QFont, QFormLayout, QFrame, QHBoxLayout, QIcon,
     QKeySequence, QLabel, QMenu, QPalette, QPlainTextEdit, QSize, QSplitter, Qt,
diff --git a/src/calibre/gui2/library/caches.py b/src/calibre/gui2/library/caches.py
index cb6a3a9876..0bac5580b6 100644
--- a/src/calibre/gui2/library/caches.py
+++ b/src/calibre/gui2/library/caches.py
@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 from threading import Lock, current_thread
 from collections import OrderedDict
 
-from PyQt5.Qt import QImage, QPixmap
+from qt.core import QImage, QPixmap
 
 from calibre.db.utils import ThumbnailCache as TC
 from polyglot.builtins import itervalues
diff --git a/src/calibre/gui2/library/delegates.py b/src/calibre/gui2/library/delegates.py
index 24b0f65816..1924778c3c 100644
--- a/src/calibre/gui2/library/delegates.py
+++ b/src/calibre/gui2/library/delegates.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import sys
 
-from PyQt5.Qt import (Qt, QApplication, QStyle, QIcon,  QDoubleSpinBox, QStyleOptionViewItem,
+from qt.core import (Qt, QApplication, QStyle, QIcon,  QDoubleSpinBox, QStyleOptionViewItem,
         QSpinBox, QStyledItemDelegate, QComboBox, QTextDocument, QMenu, QKeySequence,
         QAbstractTextDocumentLayout, QFont, QFontInfo, QDate, QDateTimeEdit, QDateTime, QEvent,
         QStyleOptionComboBox, QStyleOptionSpinBox, QLocale, QSize, QLineEdit, QDialog, QPalette)
diff --git a/src/calibre/gui2/library/models.py b/src/calibre/gui2/library/models.py
index 33996a9495..875347837f 100644
--- a/src/calibre/gui2/library/models.py
+++ b/src/calibre/gui2/library/models.py
@@ -10,7 +10,7 @@ import functools, re, os, traceback, errno, time, numbers
 from collections import defaultdict, namedtuple
 from itertools import groupby
 
-from PyQt5.Qt import (QAbstractTableModel, Qt, pyqtSignal, QIcon, QImage, QFont,
+from qt.core import (QAbstractTableModel, Qt, pyqtSignal, QIcon, QImage, QFont,
         QModelIndex, QDateTime, QColor, QPixmap, QPainter, QApplication)
 
 from calibre import fit_image, force_unicode, prepare_string_for_xml, human_readable
diff --git a/src/calibre/gui2/library/views.py b/src/calibre/gui2/library/views.py
index 2bad0212c3..f1d619eff6 100644
--- a/src/calibre/gui2/library/views.py
+++ b/src/calibre/gui2/library/views.py
@@ -10,7 +10,7 @@ import itertools, operator
 from functools import partial
 from collections import OrderedDict
 
-from PyQt5.Qt import (
+from qt.core import (
     QTableView, Qt, QAbstractItemView, QMenu, pyqtSignal, QFont, QModelIndex,
     QIcon, QItemSelection, QMimeData, QDrag, QStyle, QPoint, QUrl, QHeaderView, QEvent,
     QStyleOptionHeader, QItemSelectionModel, QSize, QFontMetrics, QApplication)
diff --git a/src/calibre/gui2/linux_file_dialogs.py b/src/calibre/gui2/linux_file_dialogs.py
index b013d90fbf..e1dd5b71f6 100644
--- a/src/calibre/gui2/linux_file_dialogs.py
+++ b/src/calibre/gui2/linux_file_dialogs.py
@@ -9,7 +9,7 @@ import sys
 import time
 from threading import Thread
 
-from PyQt5.Qt import QEventLoop
+from qt.core import QEventLoop
 
 from calibre import force_unicode
 from calibre.constants import DEBUG, filesystem_encoding, preferred_encoding
diff --git a/src/calibre/gui2/listener.py b/src/calibre/gui2/listener.py
index 21af389ba1..5d2005e2fb 100644
--- a/src/calibre/gui2/listener.py
+++ b/src/calibre/gui2/listener.py
@@ -8,7 +8,7 @@ import socket
 from contextlib import closing
 from functools import partial
 from itertools import count
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractSocket, QByteArray, QLocalServer, QLocalSocket, pyqtSignal
 )
 
@@ -122,7 +122,7 @@ def send_message_via_worker(msg, address=None, timeout=5, wait_till_sent=False):
 
 
 def test():
-    from PyQt5.Qt import QApplication, QLabel, QTimer
+    from qt.core import QApplication, QLabel, QTimer
     app = QApplication([])
     l = QLabel()
     l.setText('Waiting for message...')
diff --git a/src/calibre/gui2/lrf_renderer/bookview.py b/src/calibre/gui2/lrf_renderer/bookview.py
index b4cfe4a239..4fb1bec8fd 100644
--- a/src/calibre/gui2/lrf_renderer/bookview.py
+++ b/src/calibre/gui2/lrf_renderer/bookview.py
@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import QGraphicsView, QSize
+from qt.core import QGraphicsView, QSize
 
 
 class BookView(QGraphicsView):
diff --git a/src/calibre/gui2/lrf_renderer/document.py b/src/calibre/gui2/lrf_renderer/document.py
index 225e1147f6..bd3d72d2f7 100644
--- a/src/calibre/gui2/lrf_renderer/document.py
+++ b/src/calibre/gui2/lrf_renderer/document.py
@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import collections, itertools, glob
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QByteArray, pyqtSignal, QGraphicsRectItem, QGraphicsScene, QPen,
     QBrush, QColor, QFontDatabase, QGraphicsItem, QGraphicsLineItem)
 
diff --git a/src/calibre/gui2/lrf_renderer/main.py b/src/calibre/gui2/lrf_renderer/main.py
index f60736f50c..64de2f719b 100644
--- a/src/calibre/gui2/lrf_renderer/main.py
+++ b/src/calibre/gui2/lrf_renderer/main.py
@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys, logging, os, traceback, time
 
-from PyQt5.Qt import (
+from qt.core import (
     QKeySequence, QPainter, QDialog, QSpinBox, QSlider, QIcon, Qt, QCoreApplication, QThread, QScrollBar)
 
 from calibre import __appname__, setup_cli_handlers, islinux, isbsd, as_unicode
diff --git a/src/calibre/gui2/lrf_renderer/text.py b/src/calibre/gui2/lrf_renderer/text.py
index cb1da7bad9..3afa0e373d 100644
--- a/src/calibre/gui2/lrf_renderer/text.py
+++ b/src/calibre/gui2/lrf_renderer/text.py
@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys, collections, operator, copy, re, numbers
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QRectF, QFont, QColor, QPixmap, QGraphicsPixmapItem, QGraphicsItem,
     QFontMetrics, QPen, QBrush, QGraphicsRectItem)
 
diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index 776f8bebfb..18966f813c 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -10,7 +10,7 @@ import time
 import traceback
 
 import apsw
-from PyQt5.Qt import QCoreApplication, QIcon, QObject, QTimer
+from qt.core import QCoreApplication, QIcon, QObject, QTimer
 
 from calibre import force_unicode, prints
 from calibre.constants import (
@@ -158,7 +158,7 @@ def get_library_path(gui_runner):
     if library_path is None:  # Need to migrate to new database layout
         base = os.path.expanduser('~')
         if not base or not os.path.exists(base):
-            from PyQt5.Qt import QDir
+            from qt.core import QDir
             base = unicode_type(QDir.homePath()).replace('/', os.sep)
         candidate = gui_runner.choose_dir(base)
         if not candidate:
@@ -532,7 +532,7 @@ if __name__ == '__main__':
         if not iswindows:
             raise
         tb = traceback.format_exc()
-        from PyQt5.Qt import QErrorMessage
+        from qt.core import QErrorMessage
         logfile = os.path.join(os.path.expanduser('~'), 'calibre.log')
         if os.path.exists(logfile):
             with open(logfile) as f:
diff --git a/src/calibre/gui2/main_window.py b/src/calibre/gui2/main_window.py
index f5105175d2..c50726efa7 100644
--- a/src/calibre/gui2/main_window.py
+++ b/src/calibre/gui2/main_window.py
@@ -6,7 +6,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys, gc, weakref
 
-from PyQt5.Qt import (QMainWindow, QTimer, QAction, QMenu, QMenuBar, QIcon,
+from qt.core import (QMainWindow, QTimer, QAction, QMenu, QMenuBar, QIcon,
                       QObject, QKeySequence)
 from calibre.utils.config import OptionParser
 from calibre.gui2 import error_dialog
diff --git a/src/calibre/gui2/metadata/basic_widgets.py b/src/calibre/gui2/metadata/basic_widgets.py
index 47a41659c6..4f589300dd 100644
--- a/src/calibre/gui2/metadata/basic_widgets.py
+++ b/src/calibre/gui2/metadata/basic_widgets.py
@@ -12,7 +12,7 @@ import shutil
 import textwrap
 import weakref
 from datetime import date, datetime
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QDateTime, QDialog, QDialogButtonBox, QDoubleSpinBox, QAbstractItemView,
     QGridLayout, QIcon, QKeySequence, QLabel, QLineEdit, QListWidgetItem, QMenu,
     QMessageBox, QPixmap, QPlainTextEdit, QSize, QSizePolicy, Qt, QToolButton, QComboBox,
diff --git a/src/calibre/gui2/metadata/bulk_download.py b/src/calibre/gui2/metadata/bulk_download.py
index 7dfcf7858d..7ad4017beb 100644
--- a/src/calibre/gui2/metadata/bulk_download.py
+++ b/src/calibre/gui2/metadata/bulk_download.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os, time, shutil
 from threading import Thread
 
-from PyQt5.Qt import (QIcon, QDialog,
+from qt.core import (QIcon, QDialog,
         QDialogButtonBox, QLabel, QGridLayout, Qt)
 
 from calibre.gui2.threaded_jobs import ThreadedJob
diff --git a/src/calibre/gui2/metadata/config.py b/src/calibre/gui2/metadata/config.py
index 2953696a86..7e4cf35932 100644
--- a/src/calibre/gui2/metadata/config.py
+++ b/src/calibre/gui2/metadata/config.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import numbers
 import textwrap
-from PyQt5.Qt import (
+from qt.core import (
     QCheckBox, QComboBox, QDoubleSpinBox, QGridLayout, QGroupBox, QLabel, QLineEdit,
     QListView, QSpinBox, Qt, QVBoxLayout, QWidget
 )
diff --git a/src/calibre/gui2/metadata/diff.py b/src/calibre/gui2/metadata/diff.py
index b7126dcb7f..f3bfda3a32 100644
--- a/src/calibre/gui2/metadata/diff.py
+++ b/src/calibre/gui2/metadata/diff.py
@@ -10,7 +10,7 @@ from collections import OrderedDict, namedtuple
 from functools import partial
 from polyglot.builtins import iteritems, itervalues, zip, unicode_type, range, map
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QWidget, QGridLayout, QLabel, QToolButton, QIcon,
     QVBoxLayout, QDialogButtonBox, QApplication, pyqtSignal, QFont, QPixmap,
     QSize, QPainter, Qt, QColor, QPen, QSizePolicy, QScrollArea,
diff --git a/src/calibre/gui2/metadata/pdf_covers.py b/src/calibre/gui2/metadata/pdf_covers.py
index 8955595fb5..52adbde79f 100644
--- a/src/calibre/gui2/metadata/pdf_covers.py
+++ b/src/calibre/gui2/metadata/pdf_covers.py
@@ -10,7 +10,7 @@ import sys, shutil, os
 from threading import Thread
 from glob import glob
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QApplication, QLabel, QVBoxLayout, QDialogButtonBox, Qt, QAbstractItemView, QListView,
     pyqtSignal, QListWidget, QListWidgetItem, QSize, QPixmap, QStyledItemDelegate
 )
diff --git a/src/calibre/gui2/metadata/single.py b/src/calibre/gui2/metadata/single.py
index d650bf0150..0a8fba926f 100644
--- a/src/calibre/gui2/metadata/single.py
+++ b/src/calibre/gui2/metadata/single.py
@@ -10,7 +10,7 @@ import os, errno
 from datetime import datetime
 from functools import partial
 
-from PyQt5.Qt import (Qt, QVBoxLayout, QHBoxLayout, QWidget, QPushButton, QApplication,
+from qt.core import (Qt, QVBoxLayout, QHBoxLayout, QWidget, QPushButton, QApplication,
         QGridLayout, pyqtSignal, QDialogButtonBox, QScrollArea, QFont, QCoreApplication,
         QTabWidget, QIcon, QToolButton, QSplitter, QGroupBox, QSpacerItem, QInputDialog,
         QSizePolicy, QFrame, QSize, QKeySequence, QMenu, QShortcut, QDialog)
diff --git a/src/calibre/gui2/metadata/single_download.py b/src/calibre/gui2/metadata/single_download.py
index 4687c7ec6d..dc8a082df5 100644
--- a/src/calibre/gui2/metadata/single_download.py
+++ b/src/calibre/gui2/metadata/single_download.py
@@ -14,7 +14,7 @@ from threading import Thread, Event
 from operator import attrgetter
 from io import BytesIO
 
-from PyQt5.Qt import (
+from qt.core import (
     QStyledItemDelegate, QTextDocument, QRectF, QIcon, Qt, QApplication,
     QDialog, QVBoxLayout, QLabel, QDialogButtonBox, QStyle, QStackedWidget,
     QWidget, QTableView, QGridLayout, QPalette, QTimer, pyqtSignal,
diff --git a/src/calibre/gui2/notify.py b/src/calibre/gui2/notify.py
index 80b8f74d5e..384ddbf436 100644
--- a/src/calibre/gui2/notify.py
+++ b/src/calibre/gui2/notify.py
@@ -124,7 +124,7 @@ class QtNotifier(Notifier):
 
     def __call__(self, body, summary=None, replaces_id=None, timeout=0):
         timeout, body, summary = self.get_msg_parms(timeout, body, summary)
-        from PyQt5.Qt import QSystemTrayIcon
+        from qt.core import QSystemTrayIcon
         if self.systray is not None:
             try:
                 hide = False
diff --git a/src/calibre/gui2/open_with.py b/src/calibre/gui2/open_with.py
index afe38f57e5..d2e9218442 100644
--- a/src/calibre/gui2/open_with.py
+++ b/src/calibre/gui2/open_with.py
@@ -9,7 +9,7 @@ import os
 import uuid
 from contextlib import suppress
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QBuffer, QByteArray, QIcon, QInputDialog, QKeySequence, QLabel,
     QListWidget, QListWidgetItem, QPixmap, QSize, QStackedLayout, Qt, QVBoxLayout,
     QWidget, pyqtSignal, QIODevice, QDialogButtonBox
diff --git a/src/calibre/gui2/palette.py b/src/calibre/gui2/palette.py
index 1a41efdfb5..06371be24a 100644
--- a/src/calibre/gui2/palette.py
+++ b/src/calibre/gui2/palette.py
@@ -2,7 +2,7 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
-from PyQt5.Qt import QColor, QPalette, Qt
+from qt.core import QColor, QPalette, Qt
 from calibre.constants import dark_link_color
 
 
diff --git a/src/calibre/gui2/pin_columns.py b/src/calibre/gui2/pin_columns.py
index 4b1e17b227..029bd46fc4 100644
--- a/src/calibre/gui2/pin_columns.py
+++ b/src/calibre/gui2/pin_columns.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import QSplitter, QTableView
+from qt.core import QSplitter, QTableView
 
 from calibre.gui2.library import DEFAULT_SORT
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/preferences/__init__.py b/src/calibre/gui2/preferences/__init__.py
index 76291e6568..ee882f2d9e 100644
--- a/src/calibre/gui2/preferences/__init__.py
+++ b/src/calibre/gui2/preferences/__init__.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from PyQt5.Qt import (QWidget, pyqtSignal, QCheckBox, QAbstractSpinBox, QApplication,
+from qt.core import (QWidget, pyqtSignal, QCheckBox, QAbstractSpinBox, QApplication,
     QLineEdit, QComboBox, Qt, QIcon, QDialog, QVBoxLayout,
     QDialogButtonBox)
 
@@ -405,7 +405,7 @@ def test_widget(category, name, gui=None):
 
 
 def test_all():
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     app
     gui = init_gui()
diff --git a/src/calibre/gui2/preferences/adding.py b/src/calibre/gui2/preferences/adding.py
index e577c589ad..9d7b0e8253 100644
--- a/src/calibre/gui2/preferences/adding.py
+++ b/src/calibre/gui2/preferences/adding.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from PyQt5.Qt import Qt, QVBoxLayout, QFormLayout, QDialog
+from qt.core import Qt, QVBoxLayout, QFormLayout, QDialog
 
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget, \
     CommaSeparatedList, AbortCommit
diff --git a/src/calibre/gui2/preferences/behavior.py b/src/calibre/gui2/preferences/behavior.py
index f0e0f8818a..a0d79dfe2f 100644
--- a/src/calibre/gui2/preferences/behavior.py
+++ b/src/calibre/gui2/preferences/behavior.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import re
 from functools import partial
 
-from PyQt5.Qt import Qt, QListWidgetItem
+from qt.core import Qt, QListWidgetItem
 
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget, Setting
 from calibre.gui2.preferences.behavior_ui import Ui_Form
diff --git a/src/calibre/gui2/preferences/coloring.py b/src/calibre/gui2/preferences/coloring.py
index 93ded5e4a3..ad84f6d4cd 100644
--- a/src/calibre/gui2/preferences/coloring.py
+++ b/src/calibre/gui2/preferences/coloring.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import os, textwrap, json
 
-from PyQt5.Qt import (QWidget, QDialog, QLabel, QGridLayout, QComboBox, QSize,
+from qt.core import (QWidget, QDialog, QLabel, QGridLayout, QComboBox, QSize,
         QLineEdit, QIntValidator, QDoubleValidator, QFrame, Qt, QIcon, QHBoxLayout,
         QScrollArea, QPushButton, QVBoxLayout, QDialogButtonBox, QToolButton, QItemSelectionModel,
         QListView, QAbstractListModel, pyqtSignal, QSizePolicy, QSpacerItem, QPalette,
diff --git a/src/calibre/gui2/preferences/columns.py b/src/calibre/gui2/preferences/columns.py
index 6ec429a248..a90def0e62 100644
--- a/src/calibre/gui2/preferences/columns.py
+++ b/src/calibre/gui2/preferences/columns.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import copy, sys
 
-from PyQt5.Qt import Qt, QTableWidgetItem, QIcon
+from qt.core import Qt, QTableWidgetItem, QIcon
 
 from calibre.gui2 import gprefs, Application
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget
diff --git a/src/calibre/gui2/preferences/conversion.py b/src/calibre/gui2/preferences/conversion.py
index 26323622a4..10274cc4b7 100644
--- a/src/calibre/gui2/preferences/conversion.py
+++ b/src/calibre/gui2/preferences/conversion.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import importlib
 
-from PyQt5.Qt import (
+from qt.core import (
     QIcon, Qt, QStringListModel, QListView, QSizePolicy, QHBoxLayout, QSize,
     QStackedWidget, pyqtSignal, QScrollArea)
 
diff --git a/src/calibre/gui2/preferences/create_custom_column.py b/src/calibre/gui2/preferences/create_custom_column.py
index bfb35be8a1..7b3f51a81d 100644
--- a/src/calibre/gui2/preferences/create_custom_column.py
+++ b/src/calibre/gui2/preferences/create_custom_column.py
@@ -10,7 +10,7 @@ __copyright__ = '2010, Kovid Goyal <kovid at kovidgoyal.net>'
 import re
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, Qt, QColor, QIcon, QVBoxLayout, QLabel, QGridLayout,
     QDialogButtonBox, QWidget, QLineEdit, QHBoxLayout, QComboBox,
     QCheckBox
diff --git a/src/calibre/gui2/preferences/device_debug.py b/src/calibre/gui2/preferences/device_debug.py
index 329836a32b..68cc7e67fe 100644
--- a/src/calibre/gui2/preferences/device_debug.py
+++ b/src/calibre/gui2/preferences/device_debug.py
@@ -7,7 +7,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import QDialog, QVBoxLayout, QPlainTextEdit, QTimer, \
+from qt.core import QDialog, QVBoxLayout, QPlainTextEdit, QTimer, \
     QDialogButtonBox, QPushButton, QApplication, QIcon
 
 from calibre.gui2 import error_dialog
diff --git a/src/calibre/gui2/preferences/device_user_defined.py b/src/calibre/gui2/preferences/device_user_defined.py
index 7b2e59c7dc..7399c19db9 100644
--- a/src/calibre/gui2/preferences/device_user_defined.py
+++ b/src/calibre/gui2/preferences/device_user_defined.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 
 import numbers
-from PyQt5.Qt import QDialog, QVBoxLayout, QPlainTextEdit, QTimer, \
+from qt.core import QDialog, QVBoxLayout, QPlainTextEdit, QTimer, \
     QDialogButtonBox, QPushButton, QApplication, QIcon, QMessageBox
 
 
diff --git a/src/calibre/gui2/preferences/emailp.py b/src/calibre/gui2/preferences/emailp.py
index 3b559e4d39..77506c9eb6 100644
--- a/src/calibre/gui2/preferences/emailp.py
+++ b/src/calibre/gui2/preferences/emailp.py
@@ -6,7 +6,7 @@
 import re
 import textwrap
 
-from PyQt5.Qt import QAbstractTableModel, QFont, Qt, QAbstractItemView
+from qt.core import QAbstractTableModel, QFont, Qt, QAbstractItemView
 
 from calibre.gui2 import gprefs
 from calibre.gui2.preferences import AbortCommit, ConfigWidgetBase, test_widget
diff --git a/src/calibre/gui2/preferences/history.py b/src/calibre/gui2/preferences/history.py
index 44ff00bac7..5d677fe0e1 100644
--- a/src/calibre/gui2/preferences/history.py
+++ b/src/calibre/gui2/preferences/history.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from PyQt5.Qt import QComboBox, Qt
+from qt.core import QComboBox, Qt
 
 from calibre.gui2 import config as gui_conf
 from polyglot.builtins import unicode_type
diff --git a/src/calibre/gui2/preferences/ignored_devices.py b/src/calibre/gui2/preferences/ignored_devices.py
index d799c0f41e..04a6d9a48c 100644
--- a/src/calibre/gui2/preferences/ignored_devices.py
+++ b/src/calibre/gui2/preferences/ignored_devices.py
@@ -5,7 +5,7 @@
 
 import textwrap
 
-from PyQt5.Qt import (
+from qt.core import (
     QIcon, QLabel, QListWidget, QListWidgetItem, QPushButton, Qt, QVBoxLayout
 )
 
diff --git a/src/calibre/gui2/preferences/keyboard.py b/src/calibre/gui2/preferences/keyboard.py
index 457edb3aca..f20ad1359b 100644
--- a/src/calibre/gui2/preferences/keyboard.py
+++ b/src/calibre/gui2/preferences/keyboard.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QVBoxLayout
+from qt.core import QVBoxLayout
 
 from calibre.gui2.preferences import (ConfigWidgetBase, test_widget)
 from calibre.gui2.keyboard import ShortcutConfig
diff --git a/src/calibre/gui2/preferences/look_feel.py b/src/calibre/gui2/preferences/look_feel.py
index b1c2582715..0f685d1cca 100644
--- a/src/calibre/gui2/preferences/look_feel.py
+++ b/src/calibre/gui2/preferences/look_feel.py
@@ -11,7 +11,7 @@ import json
 from collections import defaultdict
 from threading import Thread
 
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QFont, QFontInfo, QFontDialog, QColorDialog, QPainter, QDialog,
     QAbstractListModel, Qt, QIcon, QKeySequence, QColor, pyqtSignal, QCursor,
     QWidget, QSizePolicy, QBrush, QPixmap, QSize, QPushButton, QVBoxLayout, QItemSelectionModel,
diff --git a/src/calibre/gui2/preferences/main.py b/src/calibre/gui2/preferences/main.py
index 43899895a9..dbd74e8afa 100644
--- a/src/calibre/gui2/preferences/main.py
+++ b/src/calibre/gui2/preferences/main.py
@@ -10,7 +10,7 @@ import textwrap, re
 from functools import partial
 from collections import OrderedDict
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QIcon, QFont, QWidget, QScrollArea, QStackedWidget, QVBoxLayout,
     QLabel, QFrame, QToolBar, QSize, pyqtSignal, QDialogButtonBox,
     QHBoxLayout, QDialog, QSizePolicy, QPainter, QTextLayout, QPointF,
diff --git a/src/calibre/gui2/preferences/metadata_sources.py b/src/calibre/gui2/preferences/metadata_sources.py
index c88721e7e0..e9d64ed72f 100644
--- a/src/calibre/gui2/preferences/metadata_sources.py
+++ b/src/calibre/gui2/preferences/metadata_sources.py
@@ -7,7 +7,7 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from operator import attrgetter
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, QAbstractTableModel, QDialogButtonBox, QFrame, QIcon, QLabel,
     QScrollArea, Qt, QVBoxLayout, QWidget, pyqtSignal, QDialog
 )
diff --git a/src/calibre/gui2/preferences/misc.py b/src/calibre/gui2/preferences/misc.py
index d5581e8be3..894fd8e8e9 100644
--- a/src/calibre/gui2/preferences/misc.py
+++ b/src/calibre/gui2/preferences/misc.py
@@ -71,6 +71,6 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     test_widget('Advanced', 'Misc')
diff --git a/src/calibre/gui2/preferences/plugboard.py b/src/calibre/gui2/preferences/plugboard.py
index 8affe64554..ce7e95e26f 100644
--- a/src/calibre/gui2/preferences/plugboard.py
+++ b/src/calibre/gui2/preferences/plugboard.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import copy
 from collections import defaultdict
 
-from PyQt5.Qt import Qt, QComboBox, QListWidgetItem
+from qt.core import Qt, QComboBox, QListWidgetItem
 
 from calibre.customize.ui import is_disabled
 from calibre.gui2 import error_dialog, question_dialog, warning_dialog
@@ -400,6 +400,6 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     test_widget('Import/Export', 'Plugboard')
diff --git a/src/calibre/gui2/preferences/plugins.py b/src/calibre/gui2/preferences/plugins.py
index 7001b9092b..75746fe2ad 100644
--- a/src/calibre/gui2/preferences/plugins.py
+++ b/src/calibre/gui2/preferences/plugins.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import textwrap, os
 from collections import OrderedDict
 
-from PyQt5.Qt import (Qt, QModelIndex, QAbstractItemModel, QIcon,
+from qt.core import (Qt, QModelIndex, QAbstractItemModel, QIcon,
         QBrush, QDialog, QItemSelectionModel, QAbstractItemView)
 
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget
@@ -464,6 +464,6 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     test_widget('Advanced', 'Plugins')
diff --git a/src/calibre/gui2/preferences/save_template.py b/src/calibre/gui2/preferences/save_template.py
index 94d5a568cb..09f116804b 100644
--- a/src/calibre/gui2/preferences/save_template.py
+++ b/src/calibre/gui2/preferences/save_template.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QWidget, pyqtSignal
+from qt.core import QWidget, pyqtSignal
 
 from calibre.gui2 import error_dialog, question_dialog
 from calibre.gui2.preferences.save_template_ui import Ui_Form
diff --git a/src/calibre/gui2/preferences/saving.py b/src/calibre/gui2/preferences/saving.py
index 79dda54497..c7fd72e6f6 100644
--- a/src/calibre/gui2/preferences/saving.py
+++ b/src/calibre/gui2/preferences/saving.py
@@ -55,6 +55,6 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     test_widget('Import/Export', 'Saving')
diff --git a/src/calibre/gui2/preferences/search.py b/src/calibre/gui2/preferences/search.py
index 593ac1a2b7..928d9e37fb 100644
--- a/src/calibre/gui2/preferences/search.py
+++ b/src/calibre/gui2/preferences/search.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QApplication
+from qt.core import QApplication
 
 from calibre.db.categories import find_categories
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget, \
diff --git a/src/calibre/gui2/preferences/sending.py b/src/calibre/gui2/preferences/sending.py
index d25b620251..a0505808b8 100644
--- a/src/calibre/gui2/preferences/sending.py
+++ b/src/calibre/gui2/preferences/sending.py
@@ -60,6 +60,6 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     app = QApplication([])
     test_widget('Import/Export', 'Sending')
diff --git a/src/calibre/gui2/preferences/server.py b/src/calibre/gui2/preferences/server.py
index bb5b6c5387..ba62a554cb 100644
--- a/src/calibre/gui2/preferences/server.py
+++ b/src/calibre/gui2/preferences/server.py
@@ -10,7 +10,7 @@ import sys
 import textwrap
 import time
 
-from PyQt5.Qt import (
+from qt.core import (
     QCheckBox, QComboBox, QDialog, QDialogButtonBox, QDoubleSpinBox, QFormLayout,
     QFrame, QHBoxLayout, QIcon, QLabel, QLineEdit, QListWidget, QPlainTextEdit, QLayout,
     QPushButton, QScrollArea, QSize, QSizePolicy, QSpinBox, Qt, QTabWidget, QTimer,
diff --git a/src/calibre/gui2/preferences/template_functions.py b/src/calibre/gui2/preferences/template_functions.py
index 7171058b06..6c7f63dd46 100644
--- a/src/calibre/gui2/preferences/template_functions.py
+++ b/src/calibre/gui2/preferences/template_functions.py
@@ -4,7 +4,7 @@
 
 import json
 import traceback
-from PyQt5.Qt import QDialogButtonBox
+from qt.core import QDialogButtonBox
 
 from calibre.gui2 import error_dialog, warning_dialog
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget
diff --git a/src/calibre/gui2/preferences/texture_chooser.py b/src/calibre/gui2/preferences/texture_chooser.py
index 405eef2614..89418b36cc 100644
--- a/src/calibre/gui2/preferences/texture_chooser.py
+++ b/src/calibre/gui2/preferences/texture_chooser.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import glob, os, shutil
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QVBoxLayout, QListWidget, QListWidgetItem, Qt, QIcon,
     QApplication, QSize, QDialogButtonBox, QTimer, QLabel, QAbstractItemView, QListView)
 
diff --git a/src/calibre/gui2/preferences/toolbar.py b/src/calibre/gui2/preferences/toolbar.py
index 2d5ca00cf3..5e579ccbb2 100644
--- a/src/calibre/gui2/preferences/toolbar.py
+++ b/src/calibre/gui2/preferences/toolbar.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QAbstractListModel, Qt, QIcon, QItemSelectionModel
+from qt.core import QAbstractListModel, Qt, QIcon, QItemSelectionModel
 
 from calibre import force_unicode
 from calibre.gui2.preferences.toolbar_ui import Ui_Form
diff --git a/src/calibre/gui2/preferences/tweaks.py b/src/calibre/gui2/preferences/tweaks.py
index 8136584abf..6fe1288a7b 100644
--- a/src/calibre/gui2/preferences/tweaks.py
+++ b/src/calibre/gui2/preferences/tweaks.py
@@ -8,7 +8,7 @@ from collections import OrderedDict
 from functools import partial
 from operator import attrgetter
 
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, QApplication, QDialog, QDialogButtonBox, QFont, QGridLayout,
     QGroupBox, QIcon, QLabel, QListView, QMenu, QModelIndex, QPlainTextEdit, QComboBox,
     QPushButton, QSizePolicy, QSplitter, QStyle, QStyledItemDelegate, QAbstractItemView, QItemSelectionModel,
diff --git a/src/calibre/gui2/proceed.py b/src/calibre/gui2/proceed.py
index 60d0048bc1..dd7de9774c 100644
--- a/src/calibre/gui2/proceed.py
+++ b/src/calibre/gui2/proceed.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 from collections import namedtuple
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, Qt, QLabel, QVBoxLayout, QDialogButtonBox, QApplication, QTimer, QPixmap, QEvent,
     QSize, pyqtSignal, QIcon, QPlainTextEdit, QCheckBox, QPainter, QHBoxLayout, QFontMetrics,
     QPainterPath, QRectF, pyqtProperty, QPropertyAnimation, QEasingCurve, QSizePolicy, QImage, QPalette)
@@ -406,7 +406,7 @@ class ProceedQuestion(QWidget):
 
 def main():
     from calibre.gui2 import Application
-    from PyQt5.Qt import QMainWindow, QStatusBar, QTimer
+    from qt.core import QMainWindow, QStatusBar, QTimer
     app = Application([])
     w = QMainWindow()
     s = QStatusBar(w)
diff --git a/src/calibre/gui2/progress_indicator/__init__.py b/src/calibre/gui2/progress_indicator/__init__.py
index d4fe715d9a..873117bc1c 100644
--- a/src/calibre/gui2/progress_indicator/__init__.py
+++ b/src/calibre/gui2/progress_indicator/__init__.py
@@ -2,7 +2,7 @@
 # vim:fileencoding=utf-8
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QLabel, QObject, QSizePolicy, QStackedLayout, QStackedWidget, Qt,
     QVBoxLayout, QWidget, pyqtSignal
 )
@@ -119,7 +119,7 @@ class WaitLayout(QStackedLayout):
 
 
 def develop():
-    from PyQt5.Qt import QPainter, QPalette
+    from qt.core import QPainter, QPalette
 
     from calibre.gui2 import Application
     from calibre_extensions.progress_indicator import SpinAnimator
diff --git a/src/calibre/gui2/qt_file_dialogs.py b/src/calibre/gui2/qt_file_dialogs.py
index e8ea06518a..7f6638c32b 100644
--- a/src/calibre/gui2/qt_file_dialogs.py
+++ b/src/calibre/gui2/qt_file_dialogs.py
@@ -5,7 +5,7 @@
 
 import os
 
-from PyQt5.Qt import QFileDialog, QObject
+from qt.core import QFileDialog, QObject
 
 from calibre.gui2.linux_file_dialogs import dialog_name, image_extensions
 from polyglot.builtins import unicode_type, string_or_bytes
diff --git a/src/calibre/gui2/save.py b/src/calibre/gui2/save.py
index f5597fd6c0..667724b7f5 100644
--- a/src/calibre/gui2/save.py
+++ b/src/calibre/gui2/save.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import traceback, errno, os, time, shutil
 from collections import namedtuple, defaultdict
 
-from PyQt5.Qt import QObject, Qt, pyqtSignal
+from qt.core import QObject, Qt, pyqtSignal
 
 from calibre import prints, force_unicode
 from calibre.constants import DEBUG
diff --git a/src/calibre/gui2/search_box.py b/src/calibre/gui2/search_box.py
index d6576e30c5..2a21a501d0 100644
--- a/src/calibre/gui2/search_box.py
+++ b/src/calibre/gui2/search_box.py
@@ -10,7 +10,7 @@ import re, time
 from functools import partial
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QComboBox, Qt, QLineEdit, pyqtSlot, QDialog, QEvent,
     pyqtSignal, QCompleter, QAction, QKeySequence, QTimer,
     QIcon, QMenu, QApplication, QKeyEvent)
diff --git a/src/calibre/gui2/search_restriction_mixin.py b/src/calibre/gui2/search_restriction_mixin.py
index 38b8b5062d..09e33d1cb7 100644
--- a/src/calibre/gui2/search_restriction_mixin.py
+++ b/src/calibre/gui2/search_restriction_mixin.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QMenu, QIcon, QDialog, QGridLayout, QLabel, QLineEdit, QComboBox, QFrame,
     QDialogButtonBox, QSize, QVBoxLayout, QListWidget, QRadioButton, QAction, QTextBrowser, QAbstractItemView)
 
diff --git a/src/calibre/gui2/shortcuts.py b/src/calibre/gui2/shortcuts.py
index 7cfa7fcd67..14f49d1045 100644
--- a/src/calibre/gui2/shortcuts.py
+++ b/src/calibre/gui2/shortcuts.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, Qt, QKeySequence, QListView, QVBoxLayout, QLabel, QAbstractItemView,
     QHBoxLayout, QWidget, QApplication, QStyledItemDelegate, QStyle, QIcon, QAbstractItemDelegate,
     QTextDocument, QRectF, QFrame, QSize, QFont, QKeyEvent, QRadioButton, QPushButton, QToolButton, QEvent
diff --git a/src/calibre/gui2/splash_screen.py b/src/calibre/gui2/splash_screen.py
index 467bd5709c..2487978135 100644
--- a/src/calibre/gui2/splash_screen.py
+++ b/src/calibre/gui2/splash_screen.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QBrush, QColor, QFont, QFontMetrics, QPen, QPixmap, QSplashScreen,
     Qt, QPainter
 )
diff --git a/src/calibre/gui2/store/basic_config.py b/src/calibre/gui2/store/basic_config.py
index 85a9818db7..5e9bc7c3c3 100644
--- a/src/calibre/gui2/store/basic_config.py
+++ b/src/calibre/gui2/store/basic_config.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QWidget
+from qt.core import QWidget
 
 from calibre.gui2.store.basic_config_widget_ui import Ui_Form
 from polyglot.builtins import unicode_type
diff --git a/src/calibre/gui2/store/config/chooser/adv_search_builder.py b/src/calibre/gui2/store/config/chooser/adv_search_builder.py
index 003f54b137..36e7922706 100644
--- a/src/calibre/gui2/store/config/chooser/adv_search_builder.py
+++ b/src/calibre/gui2/store/config/chooser/adv_search_builder.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import re
 
-from PyQt5.Qt import (QDialog, QDialogButtonBox)
+from qt.core import (QDialog, QDialogButtonBox)
 
 from calibre.gui2.store.config.chooser.adv_search_builder_ui import Ui_Dialog
 from calibre.library.caches import CONTAINS_MATCH, EQUALS_MATCH
diff --git a/src/calibre/gui2/store/config/chooser/chooser_dialog.py b/src/calibre/gui2/store/config/chooser/chooser_dialog.py
index 76c67efede..508bb57e90 100644
--- a/src/calibre/gui2/store/config/chooser/chooser_dialog.py
+++ b/src/calibre/gui2/store/config/chooser/chooser_dialog.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import (QDialog, QDialogButtonBox, QVBoxLayout)
+from qt.core import (QDialog, QDialogButtonBox, QVBoxLayout)
 
 from calibre.gui2.store.config.chooser.chooser_widget import StoreChooserWidget
 
diff --git a/src/calibre/gui2/store/config/chooser/chooser_widget.py b/src/calibre/gui2/store/config/chooser/chooser_widget.py
index 0740f00b4f..14d40cf42d 100644
--- a/src/calibre/gui2/store/config/chooser/chooser_widget.py
+++ b/src/calibre/gui2/store/config/chooser/chooser_widget.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QWidget, QIcon, QDialog, QComboBox, QLineEdit
+from qt.core import QWidget, QIcon, QDialog, QComboBox, QLineEdit
 
 from calibre.gui2.store.config.chooser.adv_search_builder import AdvSearchBuilderDialog
 from calibre.gui2.store.config.chooser.chooser_widget_ui import Ui_Form
diff --git a/src/calibre/gui2/store/config/chooser/models.py b/src/calibre/gui2/store/config/chooser/models.py
index bd4fe77e1f..f07362e877 100644
--- a/src/calibre/gui2/store/config/chooser/models.py
+++ b/src/calibre/gui2/store/config/chooser/models.py
@@ -6,7 +6,7 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemModel, QIcon, QModelIndex, QStyledItemDelegate, Qt
 )
 
diff --git a/src/calibre/gui2/store/config/chooser/results_view.py b/src/calibre/gui2/store/config/chooser/results_view.py
index 44f26439c2..1e53f3d66c 100644
--- a/src/calibre/gui2/store/config/chooser/results_view.py
+++ b/src/calibre/gui2/store/config/chooser/results_view.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 from functools import partial
 
-from PyQt5.Qt import (Qt, QTreeView, QSize, QMenu)
+from qt.core import (Qt, QTreeView, QSize, QMenu)
 
 from calibre.customize.ui import store_plugins
 from calibre.gui2.metadata.single_download import RichTextDelegate
diff --git a/src/calibre/gui2/store/config/search/search_widget.py b/src/calibre/gui2/store/config/search/search_widget.py
index aeb0839b10..90d3c06e0e 100644
--- a/src/calibre/gui2/store/config/search/search_widget.py
+++ b/src/calibre/gui2/store/config/search/search_widget.py
@@ -5,7 +5,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QWidget
+from qt.core import QWidget
 
 from calibre.gui2 import JSONConfig
 from calibre.gui2.store.config.search.search_widget_ui import Ui_Form
diff --git a/src/calibre/gui2/store/opensearch_store.py b/src/calibre/gui2/store/opensearch_store.py
index 67447b5e81..630b70bc83 100644
--- a/src/calibre/gui2/store/opensearch_store.py
+++ b/src/calibre/gui2/store/opensearch_store.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import (browser, guess_extension)
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/search/adv_search_builder.py b/src/calibre/gui2/store/search/adv_search_builder.py
index 9cefca355a..f984baa8ec 100644
--- a/src/calibre/gui2/store/search/adv_search_builder.py
+++ b/src/calibre/gui2/store/search/adv_search_builder.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import re
 
-from PyQt5.Qt import (QDialog, QDialogButtonBox)
+from qt.core import (QDialog, QDialogButtonBox)
 
 from calibre.gui2.store.search.adv_search_builder_ui import Ui_Dialog
 from calibre.library.caches import CONTAINS_MATCH, EQUALS_MATCH
diff --git a/src/calibre/gui2/store/search/models.py b/src/calibre/gui2/store/search/models.py
index b4c63fcb1a..94e648f1c1 100644
--- a/src/calibre/gui2/store/search/models.py
+++ b/src/calibre/gui2/store/search/models.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 import re, string
 from operator import attrgetter
 
-from PyQt5.Qt import (Qt, QAbstractItemModel, QPixmap, QModelIndex, QSize,
+from qt.core import (Qt, QAbstractItemModel, QPixmap, QModelIndex, QSize,
                       pyqtSignal, QIcon, QApplication)
 
 from calibre import force_unicode
diff --git a/src/calibre/gui2/store/search/results_view.py b/src/calibre/gui2/store/search/results_view.py
index 5388a56e54..bc738ed2ee 100644
--- a/src/calibre/gui2/store/search/results_view.py
+++ b/src/calibre/gui2/store/search/results_view.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     pyqtSignal, QMenu, QTreeView, QStyledItemDelegate, Qt, QIcon)
 
 from calibre import fit_image
diff --git a/src/calibre/gui2/store/search/search.py b/src/calibre/gui2/store/search/search.py
index 44711c978e..4cad8ff580 100644
--- a/src/calibre/gui2/store/search/search.py
+++ b/src/calibre/gui2/store/search/search.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 import re
 from random import shuffle
 
-from PyQt5.Qt import (Qt, QDialog, QDialogButtonBox, QTimer, QCheckBox, QLabel,
+from qt.core import (Qt, QDialog, QDialogButtonBox, QTimer, QCheckBox, QLabel,
                       QVBoxLayout, QIcon, QWidget, QTabWidget, QGridLayout, QApplication, QStyle)
 
 from calibre.gui2 import JSONConfig, info_dialog, error_dialog
diff --git a/src/calibre/gui2/store/stores/amazon_au_plugin.py b/src/calibre/gui2/store/stores/amazon_au_plugin.py
index 638ae0f7ed..05c14c6199 100644
--- a/src/calibre/gui2/store/stores/amazon_au_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_au_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_ca_plugin.py b/src/calibre/gui2/store/stores/amazon_ca_plugin.py
index bd4bcbde3b..cac37eb7e5 100644
--- a/src/calibre/gui2/store/stores/amazon_ca_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_ca_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_de_plugin.py b/src/calibre/gui2/store/stores/amazon_de_plugin.py
index a77fa30de5..21b22b2a80 100644
--- a/src/calibre/gui2/store/stores/amazon_de_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_de_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_es_plugin.py b/src/calibre/gui2/store/stores/amazon_es_plugin.py
index 7014664df2..d9fca8e33c 100644
--- a/src/calibre/gui2/store/stores/amazon_es_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_es_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_fr_plugin.py b/src/calibre/gui2/store/stores/amazon_fr_plugin.py
index 9f3f0bf260..f61624fbd9 100644
--- a/src/calibre/gui2/store/stores/amazon_fr_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_fr_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html, etree
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_in_plugin.py b/src/calibre/gui2/store/stores/amazon_in_plugin.py
index 1a28be4196..ca53510bd8 100644
--- a/src/calibre/gui2/store/stores/amazon_in_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_in_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_it_plugin.py b/src/calibre/gui2/store/stores/amazon_it_plugin.py
index 5b14c15d8e..58c72083fa 100644
--- a/src/calibre/gui2/store/stores/amazon_it_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_it_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_plugin.py b/src/calibre/gui2/store/stores/amazon_plugin.py
index f1972de033..a3bfb694a7 100644
--- a/src/calibre/gui2/store/stores/amazon_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html, etree
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/amazon_uk_plugin.py b/src/calibre/gui2/store/stores/amazon_uk_plugin.py
index d2b07b611d..4d464d793c 100644
--- a/src/calibre/gui2/store/stores/amazon_uk_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_uk_plugin.py
@@ -13,7 +13,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/baen_webscription_plugin.py b/src/calibre/gui2/store/stores/baen_webscription_plugin.py
index 6437ee5977..785e211e1e 100644
--- a/src/calibre/gui2/store/stores/baen_webscription_plugin.py
+++ b/src/calibre/gui2/store/stores/baen_webscription_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.ebooks.metadata import authors_to_string
diff --git a/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py b/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py
index 3e17f71a97..dca47bfa6a 100644
--- a/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py
+++ b/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py
@@ -15,7 +15,7 @@ from contextlib import closing
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/bn_plugin.py b/src/calibre/gui2/store/stores/bn_plugin.py
index 92eea8dde0..fcdcfa0656 100644
--- a/src/calibre/gui2/store/stores/bn_plugin.py
+++ b/src/calibre/gui2/store/stores/bn_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/bubok_portugal_plugin.py b/src/calibre/gui2/store/stores/bubok_portugal_plugin.py
index cc9bd96d38..dced5e721b 100644
--- a/src/calibre/gui2/store/stores/bubok_portugal_plugin.py
+++ b/src/calibre/gui2/store/stores/bubok_portugal_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/bubok_publishing_plugin.py b/src/calibre/gui2/store/stores/bubok_publishing_plugin.py
index c7bdcc16d4..281b3e1130 100644
--- a/src/calibre/gui2/store/stores/bubok_publishing_plugin.py
+++ b/src/calibre/gui2/store/stores/bubok_publishing_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/chitanka_plugin.py b/src/calibre/gui2/store/stores/chitanka_plugin.py
index 7bfa408d53..7e891babf6 100644
--- a/src/calibre/gui2/store/stores/chitanka_plugin.py
+++ b/src/calibre/gui2/store/stores/chitanka_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/ebook_nl_plugin.py b/src/calibre/gui2/store/stores/ebook_nl_plugin.py
index d348f97fb3..9ce643e073 100644
--- a/src/calibre/gui2/store/stores/ebook_nl_plugin.py
+++ b/src/calibre/gui2/store/stores/ebook_nl_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/ebookpoint_plugin.py b/src/calibre/gui2/store/stores/ebookpoint_plugin.py
index 04c8e1ca76..fe3dbf7c5d 100644
--- a/src/calibre/gui2/store/stores/ebookpoint_plugin.py
+++ b/src/calibre/gui2/store/stores/ebookpoint_plugin.py
@@ -17,7 +17,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/ebooks_com_plugin.py b/src/calibre/gui2/store/stores/ebooks_com_plugin.py
index e29c3f1d3d..8ff23b9de2 100644
--- a/src/calibre/gui2/store/stores/ebooks_com_plugin.py
+++ b/src/calibre/gui2/store/stores/ebooks_com_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py b/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py
index 2a997acab9..b6522537db 100644
--- a/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py
+++ b/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py
@@ -15,7 +15,7 @@ from contextlib import closing
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/empik_plugin.py b/src/calibre/gui2/store/stores/empik_plugin.py
index 35c3c2995c..914e63c1e1 100644
--- a/src/calibre/gui2/store/stores/empik_plugin.py
+++ b/src/calibre/gui2/store/stores/empik_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/google_books_plugin.py b/src/calibre/gui2/store/stores/google_books_plugin.py
index d816dc8c36..b2682b4a4e 100644
--- a/src/calibre/gui2/store/stores/google_books_plugin.py
+++ b/src/calibre/gui2/store/stores/google_books_plugin.py
@@ -14,7 +14,7 @@ except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/legimi_plugin.py b/src/calibre/gui2/store/stores/legimi_plugin.py
index 0183190e4d..c3d41c0870 100644
--- a/src/calibre/gui2/store/stores/legimi_plugin.py
+++ b/src/calibre/gui2/store/stores/legimi_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/libri_de_plugin.py b/src/calibre/gui2/store/stores/libri_de_plugin.py
index d0a5125836..701844674b 100644
--- a/src/calibre/gui2/store/stores/libri_de_plugin.py
+++ b/src/calibre/gui2/store/stores/libri_de_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/litres_plugin.py b/src/calibre/gui2/store/stores/litres_plugin.py
index 128cbbcf2d..16c38806c3 100644
--- a/src/calibre/gui2/store/stores/litres_plugin.py
+++ b/src/calibre/gui2/store/stores/litres_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from contextlib import closing
 from lxml import etree
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner, prints
 from calibre.ebooks.chardet import xml_to_unicode
diff --git a/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py b/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py
index 84bd76b3f1..1f65c9e708 100644
--- a/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py
+++ b/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py b/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py
index 0c69a55e98..883f0c34f2 100644
--- a/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py
+++ b/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import re
 
-from PyQt5.Qt import (QDialog, QDialogButtonBox)
+from qt.core import (QDialog, QDialogButtonBox)
 
 from calibre.gui2.store.stores.mobileread.adv_search_builder_ui import Ui_Dialog
 from calibre.library.caches import CONTAINS_MATCH, EQUALS_MATCH
diff --git a/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py b/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py
index 4361b72504..b8baff7360 100644
--- a/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py
+++ b/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py
@@ -6,7 +6,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from PyQt5.Qt import QDialog
+from qt.core import QDialog
 
 from calibre.gui2.store.stores.mobileread.cache_progress_dialog_ui import Ui_Dialog
 
diff --git a/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py b/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py
index 3eac912782..4a410e684f 100644
--- a/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py
+++ b/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py
@@ -12,7 +12,7 @@ from threading import Thread
 
 from lxml import html
 
-from PyQt5.Qt import (pyqtSignal, QObject)
+from qt.core import (pyqtSignal, QObject)
 
 from calibre import browser
 from calibre.gui2.store.search_result import SearchResult
diff --git a/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py b/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py
index ae764f5e60..d9c3e87dc0 100644
--- a/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py
+++ b/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os
 from threading import Lock
 
-from PyQt5.Qt import (QUrl, QCoreApplication)
+from qt.core import (QUrl, QCoreApplication)
 
 from calibre.constants import cache_dir
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/mobileread/models.py b/src/calibre/gui2/store/stores/mobileread/models.py
index 9d5f0495e0..5d4430cc6c 100644
--- a/src/calibre/gui2/store/stores/mobileread/models.py
+++ b/src/calibre/gui2/store/stores/mobileread/models.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 from operator import attrgetter
 
-from PyQt5.Qt import (Qt, QAbstractItemModel, QModelIndex, pyqtSignal)
+from qt.core import (Qt, QAbstractItemModel, QModelIndex, pyqtSignal)
 
 from calibre.db.search import _match, CONTAINS_MATCH, EQUALS_MATCH, REGEXP_MATCH
 from calibre.utils.config_base import prefs
diff --git a/src/calibre/gui2/store/stores/mobileread/store_dialog.py b/src/calibre/gui2/store/stores/mobileread/store_dialog.py
index 420dbc99ff..7303fb3a86 100644
--- a/src/calibre/gui2/store/stores/mobileread/store_dialog.py
+++ b/src/calibre/gui2/store/stores/mobileread/store_dialog.py
@@ -7,7 +7,7 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import (Qt, QDialog, QIcon, QComboBox, QApplication)
+from qt.core import (Qt, QDialog, QIcon, QComboBox, QApplication)
 
 from calibre.gui2.store.stores.mobileread.adv_search_builder import AdvSearchBuilderDialog
 from calibre.gui2.store.stores.mobileread.models import BooksModel
diff --git a/src/calibre/gui2/store/stores/nexto_plugin.py b/src/calibre/gui2/store/stores/nexto_plugin.py
index 3e25dad8f6..3199787d8d 100644
--- a/src/calibre/gui2/store/stores/nexto_plugin.py
+++ b/src/calibre/gui2/store/stores/nexto_plugin.py
@@ -17,7 +17,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/ozon_ru_plugin.py b/src/calibre/gui2/store/stores/ozon_ru_plugin.py
index 1352d2b9a9..c3afbe1cb5 100644
--- a/src/calibre/gui2/store/stores/ozon_ru_plugin.py
+++ b/src/calibre/gui2/store/stores/ozon_ru_plugin.py
@@ -13,7 +13,7 @@ try:
 except ImportError:
     from urllib import quote_plus
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.ebooks.chardet import xml_to_unicode
diff --git a/src/calibre/gui2/store/stores/publio_plugin.py b/src/calibre/gui2/store/stores/publio_plugin.py
index da5fdee3bf..496ffa86d5 100644
--- a/src/calibre/gui2/store/stores/publio_plugin.py
+++ b/src/calibre/gui2/store/stores/publio_plugin.py
@@ -16,7 +16,7 @@ from contextlib import closing
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/rw2010_plugin.py b/src/calibre/gui2/store/stores/rw2010_plugin.py
index 095774ae4b..f57af28270 100644
--- a/src/calibre/gui2/store/stores/rw2010_plugin.py
+++ b/src/calibre/gui2/store/stores/rw2010_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/smashwords_plugin.py b/src/calibre/gui2/store/stores/smashwords_plugin.py
index 2b93a524f2..4d9cdf37fa 100644
--- a/src/calibre/gui2/store/stores/smashwords_plugin.py
+++ b/src/calibre/gui2/store/stores/smashwords_plugin.py
@@ -17,7 +17,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/swiatebookow_plugin.py b/src/calibre/gui2/store/stores/swiatebookow_plugin.py
index a8d582ceb1..b67adf5d4f 100644
--- a/src/calibre/gui2/store/stores/swiatebookow_plugin.py
+++ b/src/calibre/gui2/store/stores/swiatebookow_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/virtualo_plugin.py b/src/calibre/gui2/store/stores/virtualo_plugin.py
index 974292b0ef..4ddf691471 100644
--- a/src/calibre/gui2/store/stores/virtualo_plugin.py
+++ b/src/calibre/gui2/store/stores/virtualo_plugin.py
@@ -17,7 +17,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/weightless_books_plugin.py b/src/calibre/gui2/store/stores/weightless_books_plugin.py
index c5db05cee6..c6215b85ba 100644
--- a/src/calibre/gui2/store/stores/weightless_books_plugin.py
+++ b/src/calibre/gui2/store/stores/weightless_books_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/whsmith_uk_plugin.py b/src/calibre/gui2/store/stores/whsmith_uk_plugin.py
index 966ad70201..655ab29ec3 100644
--- a/src/calibre/gui2/store/stores/whsmith_uk_plugin.py
+++ b/src/calibre/gui2/store/stores/whsmith_uk_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/woblink_plugin.py b/src/calibre/gui2/store/stores/woblink_plugin.py
index 6d6fa4e2be..027ecbfdd9 100644
--- a/src/calibre/gui2/store/stores/woblink_plugin.py
+++ b/src/calibre/gui2/store/stores/woblink_plugin.py
@@ -16,7 +16,7 @@ except ImportError:
 from lxml import html
 from mechanize import Request
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import url_slash_cleaner, browser
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/stores/wolnelektury_plugin.py b/src/calibre/gui2/store/stores/wolnelektury_plugin.py
index 0c7dfba06e..a912595a32 100644
--- a/src/calibre/gui2/store/stores/wolnelektury_plugin.py
+++ b/src/calibre/gui2/store/stores/wolnelektury_plugin.py
@@ -15,7 +15,7 @@ except ImportError:
 
 from lxml import html
 
-from PyQt5.Qt import QUrl
+from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
diff --git a/src/calibre/gui2/store/web_store.py b/src/calibre/gui2/store/web_store.py
index 23707299b5..94533ec7c3 100644
--- a/src/calibre/gui2/store/web_store.py
+++ b/src/calibre/gui2/store/web_store.py
@@ -6,11 +6,11 @@
 import json
 import os
 import shutil
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QHBoxLayout, QIcon, QLabel, QProgressBar, QPushButton, QSize, QUrl,
     QVBoxLayout, QWidget, pyqtSignal
 )
-from PyQt5.QtWebEngineWidgets import QWebEngineProfile, QWebEngineView, QWebEngineDownloadItem
+from qt.webengine import QWebEngineProfile, QWebEngineView, QWebEngineDownloadItem
 
 from calibre import random_user_agent, url_slash_cleaner
 from calibre.constants import STORE_DIALOG_APP_UID, cache_dir, islinux, iswindows
diff --git a/src/calibre/gui2/tag_browser/model.py b/src/calibre/gui2/tag_browser/model.py
index 8af95ad31c..c05c638d71 100644
--- a/src/calibre/gui2/tag_browser/model.py
+++ b/src/calibre/gui2/tag_browser/model.py
@@ -10,7 +10,7 @@ import copy
 import os
 import traceback
 from collections import OrderedDict, namedtuple
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemModel, QFont, QIcon, QMimeData, QModelIndex, QObject, Qt,
     pyqtSignal
 )
diff --git a/src/calibre/gui2/tag_browser/ui.py b/src/calibre/gui2/tag_browser/ui.py
index 41c1a35fb5..f26eac35b8 100644
--- a/src/calibre/gui2/tag_browser/ui.py
+++ b/src/calibre/gui2/tag_browser/ui.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import textwrap
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QIcon, QWidget, QHBoxLayout, QVBoxLayout, QToolButton, QLabel, QFrame, QDialog, QComboBox, QLineEdit,
     QTimer, QMenu, QActionGroup, QAction, QSizePolicy, pyqtSignal)
 
diff --git a/src/calibre/gui2/tag_browser/view.py b/src/calibre/gui2/tag_browser/view.py
index aa1ab7a38c..43b54d542c 100644
--- a/src/calibre/gui2/tag_browser/view.py
+++ b/src/calibre/gui2/tag_browser/view.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os, re, traceback
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     QStyledItemDelegate, Qt, QTreeView, pyqtSignal, QSize, QIcon, QApplication, QStyle, QAbstractItemView,
     QMenu, QPoint, QToolTip, QCursor, QDrag, QRect, QModelIndex,
     QLinearGradient, QPalette, QColor, QPen, QBrush, QFont, QTimer
diff --git a/src/calibre/gui2/tag_mapper.py b/src/calibre/gui2/tag_mapper.py
index 0f8144e5f0..a3b4742d61 100644
--- a/src/calibre/gui2/tag_mapper.py
+++ b/src/calibre/gui2/tag_mapper.py
@@ -6,7 +6,7 @@
 from collections import OrderedDict
 import textwrap
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, QVBoxLayout, QHBoxLayout, QPushButton, QLabel, QListWidget, QIcon, QDialog,
     QSize, QComboBox, QLineEdit, QListWidgetItem, QStyledItemDelegate, QAbstractItemView,
     QStaticText, Qt, QStyle, QToolButton, QInputDialog, QMenu, pyqtSignal, QPalette, QItemSelectionModel, QDialogButtonBox
diff --git a/src/calibre/gui2/throbber.py b/src/calibre/gui2/throbber.py
index b09b4eafb1..c0cc280267 100644
--- a/src/calibre/gui2/throbber.py
+++ b/src/calibre/gui2/throbber.py
@@ -7,7 +7,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QToolButton, QSize, QPropertyAnimation, Qt, QMetaObject, pyqtProperty, QSizePolicy,
     QWidget, QIcon, QPainter, QStyleOptionToolButton, QStyle, QAbstractAnimation)
 
@@ -77,7 +77,7 @@ class ThrobbingButton(QToolButton):
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QApplication, QHBoxLayout
+    from qt.core import QApplication, QHBoxLayout
     app = QApplication([])
     w = QWidget()
     w.setLayout(QHBoxLayout())
diff --git a/src/calibre/gui2/toc/location.py b/src/calibre/gui2/toc/location.py
index 71316776f5..21d0f27c22 100644
--- a/src/calibre/gui2/toc/location.py
+++ b/src/calibre/gui2/toc/location.py
@@ -5,11 +5,11 @@
 
 import json
 
-from PyQt5.Qt import (
+from qt.core import (
     QFrame, QGridLayout, QIcon, QLabel, QLineEdit, QListWidget, QPushButton, QSize,
     QSplitter, Qt, QUrl, QVBoxLayout, QWidget, pyqtSignal
 )
-from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineScript, QWebEngineView
+from qt.webengine import QWebEnginePage, QWebEngineScript, QWebEngineView
 
 from calibre.gui2 import error_dialog, gprefs, question_dialog
 from calibre.gui2.webengine import secure_webengine
diff --git a/src/calibre/gui2/toc/main.py b/src/calibre/gui2/toc/main.py
index 3f9dc1e9c6..4dbcb0b00b 100644
--- a/src/calibre/gui2/toc/main.py
+++ b/src/calibre/gui2/toc/main.py
@@ -7,7 +7,7 @@ import os
 import sys
 import textwrap
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QCheckBox, QCursor, QDialog, QDialogButtonBox, QFrame, QGridLayout,
     QIcon, QInputDialog, QItemSelectionModel, QKeySequence, QLabel, QMenu,
     QPushButton, QScrollArea, QSize, QSizePolicy, QStackedWidget, Qt, QAbstractItemView,
diff --git a/src/calibre/gui2/tools.py b/src/calibre/gui2/tools.py
index db0705fc67..d2874a0cea 100644
--- a/src/calibre/gui2/tools.py
+++ b/src/calibre/gui2/tools.py
@@ -11,7 +11,7 @@ Logic for setting up conversion jobs
 
 import os
 
-from PyQt5.Qt import QDialog, QProgressDialog, QTimer
+from qt.core import QDialog, QProgressDialog, QTimer
 
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.gui2 import warning_dialog, question_dialog
diff --git a/src/calibre/gui2/tts/develop.py b/src/calibre/gui2/tts/develop.py
index 1541098817..6872263550 100644
--- a/src/calibre/gui2/tts/develop.py
+++ b/src/calibre/gui2/tts/develop.py
@@ -5,7 +5,7 @@
 
 import re
 from itertools import count
-from PyQt5.Qt import (
+from qt.core import (
     QDialogButtonBox, QLabel, QMainWindow, Qt, QTimer, QVBoxLayout, QWidget,
     pyqtSignal
 )
diff --git a/src/calibre/gui2/tts/linux_config.py b/src/calibre/gui2/tts/linux_config.py
index d0d099a830..eaf589648f 100644
--- a/src/calibre/gui2/tts/linux_config.py
+++ b/src/calibre/gui2/tts/linux_config.py
@@ -3,7 +3,7 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemView, QAbstractTableModel, QByteArray, QComboBox, QFontMetrics,
     QFormLayout, QItemSelectionModel, QSlider, QSortFilterProxyModel, Qt, QTableView,
     QWidget
diff --git a/src/calibre/gui2/tts/macos_config.py b/src/calibre/gui2/tts/macos_config.py
index b6831ff207..c9e8389000 100644
--- a/src/calibre/gui2/tts/macos_config.py
+++ b/src/calibre/gui2/tts/macos_config.py
@@ -3,7 +3,7 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemView, QAbstractTableModel, QByteArray, QFontMetrics, QFormLayout,
     QItemSelectionModel, QSlider, QSortFilterProxyModel, Qt, QTableView, QWidget
 )
diff --git a/src/calibre/gui2/tts/windows_config.py b/src/calibre/gui2/tts/windows_config.py
index 129797fed3..16a2337b34 100644
--- a/src/calibre/gui2/tts/windows_config.py
+++ b/src/calibre/gui2/tts/windows_config.py
@@ -3,7 +3,7 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemView, QAbstractTableModel, QByteArray, QComboBox, QFontMetrics,
     QFormLayout, QItemSelectionModel, QSlider, QSortFilterProxyModel, Qt, QTableView,
     QWidget
diff --git a/src/calibre/gui2/tweak_book/boss.py b/src/calibre/gui2/tweak_book/boss.py
index dd7bc62a37..75ab6a1d3e 100644
--- a/src/calibre/gui2/tweak_book/boss.py
+++ b/src/calibre/gui2/tweak_book/boss.py
@@ -10,7 +10,7 @@ import sys
 import tempfile
 from functools import partial, wraps
 
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon,
     QInputDialog, QLabel, QMimeData, QObject, QSize, Qt, QTimer, QUrl, QVBoxLayout,
     pyqtSignal
diff --git a/src/calibre/gui2/tweak_book/char_select.py b/src/calibre/gui2/tweak_book/char_select.py
index 27d0252b3d..8210a7a012 100644
--- a/src/calibre/gui2/tweak_book/char_select.py
+++ b/src/calibre/gui2/tweak_book/char_select.py
@@ -9,7 +9,7 @@ import re
 import textwrap
 from bisect import bisect
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractItemModel, QAbstractListModel, QApplication, QCheckBox, QGridLayout,
     QHBoxLayout, QIcon, QInputMethodEvent, QLabel, QListView, QMenu, QMimeData,
     QModelIndex, QPen, QPushButton, QSize, QSizePolicy, QSplitter,
diff --git a/src/calibre/gui2/tweak_book/check.py b/src/calibre/gui2/tweak_book/check.py
index 666ef8438b..1821af5fff 100644
--- a/src/calibre/gui2/tweak_book/check.py
+++ b/src/calibre/gui2/tweak_book/check.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
 
-from PyQt5.Qt import (
+from qt.core import (
      QIcon, Qt, QSplitter, QListWidget, QTextBrowser, QPalette, QMenu,
      QListWidgetItem, pyqtSignal, QApplication, QStyledItemDelegate,
      QAbstractItemView)
diff --git a/src/calibre/gui2/tweak_book/check_links.py b/src/calibre/gui2/tweak_book/check_links.py
index dd8e4b0e70..9e2c2f34d1 100644
--- a/src/calibre/gui2/tweak_book/check_links.py
+++ b/src/calibre/gui2/tweak_book/check_links.py
@@ -6,7 +6,7 @@
 from collections import defaultdict
 from threading import Thread
 
-from PyQt5.Qt import (
+from qt.core import (
     QCheckBox, QHBoxLayout, QIcon, QInputDialog, QLabel, QProgressBar, QSizePolicy,
     QStackedWidget, Qt, QTextBrowser, QVBoxLayout, QWidget, pyqtSignal, QDialogButtonBox
 )
diff --git a/src/calibre/gui2/tweak_book/completion/basic.py b/src/calibre/gui2/tweak_book/completion/basic.py
index 5c55c13764..a0df293ee9 100644
--- a/src/calibre/gui2/tweak_book/completion/basic.py
+++ b/src/calibre/gui2/tweak_book/completion/basic.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from threading import Event
 from collections import namedtuple, OrderedDict
 
-from PyQt5.Qt import QObject, pyqtSignal, Qt
+from qt.core import QObject, pyqtSignal, Qt
 
 from calibre import prepare_string_for_xml
 from calibre.ebooks.oeb.polish.container import OEB_STYLES, OEB_FONTS, name_to_href
diff --git a/src/calibre/gui2/tweak_book/completion/popup.py b/src/calibre/gui2/tweak_book/completion/popup.py
index 047f3a9ad7..2ba5689468 100644
--- a/src/calibre/gui2/tweak_book/completion/popup.py
+++ b/src/calibre/gui2/tweak_book/completion/popup.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import textwrap
 from math import ceil
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, Qt, QStaticText, QTextOption, QSize, QPainter, QTimer, QPalette, QEvent, QTextCursor)
 
 from calibre import prints, prepare_string_for_xml
diff --git a/src/calibre/gui2/tweak_book/diff/highlight.py b/src/calibre/gui2/tweak_book/diff/highlight.py
index f569094106..4e47451454 100644
--- a/src/calibre/gui2/tweak_book/diff/highlight.py
+++ b/src/calibre/gui2/tweak_book/diff/highlight.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 
-from PyQt5.Qt import QTextDocument, QTextCursor, QPlainTextDocumentLayout
+from qt.core import QTextDocument, QTextCursor, QPlainTextDocumentLayout
 
 from calibre.gui2.tweak_book import tprefs
 from calibre.gui2.tweak_book.editor.text import get_highlighter as calibre_highlighter, SyntaxHighlighter
diff --git a/src/calibre/gui2/tweak_book/diff/main.py b/src/calibre/gui2/tweak_book/diff/main.py
index c1bd6a6c7f..55b2e440f5 100644
--- a/src/calibre/gui2/tweak_book/diff/main.py
+++ b/src/calibre/gui2/tweak_book/diff/main.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import sys, os, re
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     QGridLayout, QToolButton, QIcon, QRadioButton, QMenu, QApplication, Qt,
     QSize, QWidget, QLabel, QStackedLayout, QPainter, QRect, QVBoxLayout,
     QCursor, QEventLoop, QKeySequence, pyqtSignal, QTimer, QHBoxLayout, QDialogButtonBox)
diff --git a/src/calibre/gui2/tweak_book/diff/view.py b/src/calibre/gui2/tweak_book/diff/view.py
index ff30021653..b257f60650 100644
--- a/src/calibre/gui2/tweak_book/diff/view.py
+++ b/src/calibre/gui2/tweak_book/diff/view.py
@@ -14,7 +14,7 @@ from difflib import SequenceMatcher
 from polyglot.builtins import iteritems, unicode_type, zip, range, as_bytes, map
 
 import regex
-from PyQt5.Qt import (
+from qt.core import (
     QSplitter, QApplication, QTimer, QEvent,
     QTextCursor, QTextCharFormat, Qt, QRect, QPainter, QPalette, QPen, QBrush,
     QColor, QTextLayout, QCursor, QFont, QSplitterHandle, QPainterPath, QPlainTextEdit,
diff --git a/src/calibre/gui2/tweak_book/download.py b/src/calibre/gui2/tweak_book/download.py
index 85fad49faa..15d6c7bb6b 100644
--- a/src/calibre/gui2/tweak_book/download.py
+++ b/src/calibre/gui2/tweak_book/download.py
@@ -5,7 +5,7 @@
 
 from threading import Thread
 
-from PyQt5.Qt import (
+from qt.core import (
     pyqtSignal, QWidget, QListWidget, QListWidgetItem, QLabel, Qt,
     QVBoxLayout, QScrollArea, QProgressBar, QGridLayout, QSize, QIcon, QDialogButtonBox)
 
diff --git a/src/calibre/gui2/tweak_book/editor/__init__.py b/src/calibre/gui2/tweak_book/editor/__init__.py
index 573e5be9f6..ffc54590ca 100644
--- a/src/calibre/gui2/tweak_book/editor/__init__.py
+++ b/src/calibre/gui2/tweak_book/editor/__init__.py
@@ -5,7 +5,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import QTextCharFormat, QTextFormat
+from qt.core import QTextCharFormat, QTextFormat
 
 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES
 from calibre.ebooks.oeb.polish.container import guess_type
diff --git a/src/calibre/gui2/tweak_book/editor/canvas.py b/src/calibre/gui2/tweak_book/editor/canvas.py
index e911b50454..def50a61d2 100644
--- a/src/calibre/gui2/tweak_book/editor/canvas.py
+++ b/src/calibre/gui2/tweak_book/editor/canvas.py
@@ -9,7 +9,7 @@ import sys, weakref
 from functools import wraps
 from io import BytesIO
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, QPainter, QColor, QApplication, Qt, QPixmap, QRectF, QTransform,
     QPointF, QPen, pyqtSignal, QUndoCommand, QUndoStack, QIcon, QImage,
     QImageWriter)
diff --git a/src/calibre/gui2/tweak_book/editor/comments.py b/src/calibre/gui2/tweak_book/editor/comments.py
index a4e139e71f..6b5b38570d 100644
--- a/src/calibre/gui2/tweak_book/editor/comments.py
+++ b/src/calibre/gui2/tweak_book/editor/comments.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import QTextCursor, QTextDocument
+from qt.core import QTextCursor, QTextDocument
 
 opening_map = {
     'css':'/*',
diff --git a/src/calibre/gui2/tweak_book/editor/image.py b/src/calibre/gui2/tweak_book/editor/image.py
index 62d3b77301..f5e704a29c 100644
--- a/src/calibre/gui2/tweak_book/editor/image.py
+++ b/src/calibre/gui2/tweak_book/editor/image.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
 
-from PyQt5.Qt import (
+from qt.core import (
     QMainWindow, Qt, QApplication, pyqtSignal, QLabel, QIcon, QFormLayout, QSize,
     QDialog, QSpinBox, QCheckBox, QDialogButtonBox, QToolButton, QMenu, QInputDialog)
 
diff --git a/src/calibre/gui2/tweak_book/editor/insert_resource.py b/src/calibre/gui2/tweak_book/editor/insert_resource.py
index 4addc8dedd..4b83ae4785 100644
--- a/src/calibre/gui2/tweak_book/editor/insert_resource.py
+++ b/src/calibre/gui2/tweak_book/editor/insert_resource.py
@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import os
 import sys
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, QApplication, QCheckBox, QFormLayout, QGridLayout, QClipboard,
     QHBoxLayout, QIcon, QInputDialog, QLabel, QLineEdit, QListView, QMenu, QPainter,
     QPixmap, QRect, QSize, QSizePolicy, QSortFilterProxyModel, QStyledItemDelegate,
diff --git a/src/calibre/gui2/tweak_book/editor/smarts/css.py b/src/calibre/gui2/tweak_book/editor/smarts/css.py
index bf2ba3df71..de70107470 100644
--- a/src/calibre/gui2/tweak_book/editor/smarts/css.py
+++ b/src/calibre/gui2/tweak_book/editor/smarts/css.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 
-from PyQt5.Qt import Qt, QTextCursor
+from qt.core import Qt, QTextCursor
 
 from calibre.gui2.tweak_book import current_container
 from calibre.gui2.tweak_book.editor.smarts import NullSmarts
diff --git a/src/calibre/gui2/tweak_book/editor/smarts/html.py b/src/calibre/gui2/tweak_book/editor/smarts/html.py
index 340c2c1666..e7691b402c 100644
--- a/src/calibre/gui2/tweak_book/editor/smarts/html.py
+++ b/src/calibre/gui2/tweak_book/editor/smarts/html.py
@@ -11,7 +11,7 @@ from contextlib import contextmanager
 from css_parser import parseStyle
 from itertools import chain
 from operator import itemgetter
-from PyQt5.Qt import Qt, QTextCursor, QTextEdit
+from qt.core import Qt, QTextCursor, QTextEdit
 
 from calibre import prepare_string_for_xml, xml_entity_to_unicode
 from calibre.ebooks.oeb.base import css_text
diff --git a/src/calibre/gui2/tweak_book/editor/smarts/python.py b/src/calibre/gui2/tweak_book/editor/smarts/python.py
index 62c7288fd8..cecb4c7703 100644
--- a/src/calibre/gui2/tweak_book/editor/smarts/python.py
+++ b/src/calibre/gui2/tweak_book/editor/smarts/python.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 
-from PyQt5.Qt import Qt
+from qt.core import Qt
 
 from calibre.gui2.tweak_book.editor.smarts import NullSmarts
 from calibre.gui2.tweak_book.editor.smarts.utils import (
diff --git a/src/calibre/gui2/tweak_book/editor/smarts/utils.py b/src/calibre/gui2/tweak_book/editor/smarts/utils.py
index bdea4ec7e5..4bcc351f98 100644
--- a/src/calibre/gui2/tweak_book/editor/smarts/utils.py
+++ b/src/calibre/gui2/tweak_book/editor/smarts/utils.py
@@ -5,7 +5,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import Qt, QTextCursor
+from qt.core import Qt, QTextCursor
 
 
 def get_text_around_cursor(editor, before=True):
diff --git a/src/calibre/gui2/tweak_book/editor/snippets.py b/src/calibre/gui2/tweak_book/editor/snippets.py
index 7ab6ab4b7b..322c3d4261 100644
--- a/src/calibre/gui2/tweak_book/editor/snippets.py
+++ b/src/calibre/gui2/tweak_book/editor/snippets.py
@@ -10,7 +10,7 @@ from collections import OrderedDict, namedtuple
 from itertools import groupby
 from operator import attrgetter, itemgetter
 
-from PyQt5.Qt import (
+from qt.core import (
     Qt, QObject, QSize, QVBoxLayout, QStackedLayout, QWidget, QLineEdit, QListView,
     QToolButton, QIcon, QHBoxLayout, QPushButton, QListWidget, QListWidgetItem,
     QGridLayout, QPlainTextEdit, QLabel, QFrame, QDialog, QDialogButtonBox, QTextCursor)
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/base.py b/src/calibre/gui2/tweak_book/editor/syntax/base.py
index ac1442b4bf..5d75a0a589 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/base.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/base.py
@@ -6,7 +6,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import defaultdict, deque
 
-from PyQt5.Qt import QTextCursor, QTextBlockUserData, QTextLayout, QTimer
+from qt.core import QTextCursor, QTextBlockUserData, QTextLayout, QTimer
 
 from ..themes import highlight_to_char_format
 from calibre.gui2.tweak_book.widgets import BusyCursor
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/css.py b/src/calibre/gui2/tweak_book/editor/syntax/css.py
index d8a3758ff8..b1349e5381 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/css.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/css.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 
-from PyQt5.Qt import QTextBlockUserData
+from qt.core import QTextBlockUserData
 
 from calibre.gui2.tweak_book import verify_link
 from calibre.gui2.tweak_book.editor import syntax_text_char_format, LINK_PROPERTY, CSS_PROPERTY
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/html.py b/src/calibre/gui2/tweak_book/editor/syntax/html.py
index 074d8483de..a1ec0a1afa 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/html.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/html.py
@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import re
 from collections import namedtuple
 from functools import partial
-from PyQt5.Qt import QFont, QTextBlockUserData, QTextCharFormat
+from qt.core import QFont, QTextBlockUserData, QTextCharFormat
 
 from calibre.ebooks.oeb.polish.spell import html_spell_tags, patterns, xml_spell_tags
 from calibre.gui2.tweak_book import dictionaries, tprefs, verify_link
@@ -522,7 +522,7 @@ class XMLHighlighter(Highlighter):
 
 def profile():
     import sys
-    from PyQt5.Qt import QTextDocument
+    from qt.core import QTextDocument
 
     from calibre.gui2 import Application
     from calibre.gui2.tweak_book import set_book_locale
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py b/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py
index 64f7385ad0..1dee126e30 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import numbers
 from functools import partial
 
-from PyQt5.Qt import QTextBlockUserData
+from qt.core import QTextBlockUserData
 from pygments.lexer import _TokenType, Error
 
 from calibre.gui2.tweak_book.editor.syntax.base import SyntaxHighlighter
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/utils.py b/src/calibre/gui2/tweak_book/editor/syntax/utils.py
index 7a18ebee7a..650548a604 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/utils.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/utils.py
@@ -5,7 +5,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import QTextCharFormat
+from qt.core import QTextCharFormat
 
 NULL_FMT = QTextCharFormat()
 
diff --git a/src/calibre/gui2/tweak_book/editor/text.py b/src/calibre/gui2/tweak_book/editor/text.py
index 194cec6752..d4a47bf132 100644
--- a/src/calibre/gui2/tweak_book/editor/text.py
+++ b/src/calibre/gui2/tweak_book/editor/text.py
@@ -9,7 +9,7 @@ import re
 import regex
 import textwrap
 import unicodedata
-from PyQt5.Qt import (
+from qt.core import (
     QColor, QColorDialog, QFont, QFontDatabase, QKeySequence, QPainter, QPalette,
     QPlainTextEdit, QRect, QSize, Qt, QTextCursor, QTextEdit, QTextFormat, QTimer,
     QToolTip, QWidget, pyqtSignal
diff --git a/src/calibre/gui2/tweak_book/editor/themes.py b/src/calibre/gui2/tweak_book/editor/themes.py
index 9c5c5a110c..0ad80ca500 100644
--- a/src/calibre/gui2/tweak_book/editor/themes.py
+++ b/src/calibre/gui2/tweak_book/editor/themes.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import namedtuple
 
-from PyQt5.Qt import (
+from qt.core import (
     QColor, QBrush, QFont, QApplication, QPalette, QComboBox,
     QPushButton, QIcon, QFormLayout, QLineEdit, QWidget, QScrollArea,
     QVBoxLayout, Qt, QHBoxLayout, pyqtSignal, QPixmap, QColorDialog, QDialog,
diff --git a/src/calibre/gui2/tweak_book/editor/widget.py b/src/calibre/gui2/tweak_book/editor/widget.py
index 77f8740d4b..0e2e8aeb7a 100644
--- a/src/calibre/gui2/tweak_book/editor/widget.py
+++ b/src/calibre/gui2/tweak_book/editor/widget.py
@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import math
 import unicodedata
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QColor, QIcon, QImage, QInputDialog, QMainWindow, QMenu,
     QPainter, QPixmap, QSize, Qt, QTextCursor, QToolButton, pyqtSignal,
     qDrawShadeRect
diff --git a/src/calibre/gui2/tweak_book/file_list.py b/src/calibre/gui2/tweak_book/file_list.py
index 3211e6708f..40e9c57c56 100644
--- a/src/calibre/gui2/tweak_book/file_list.py
+++ b/src/calibre/gui2/tweak_book/file_list.py
@@ -9,7 +9,7 @@ import sys
 import textwrap
 from collections import Counter, OrderedDict, defaultdict
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QCheckBox, QDialog, QDialogButtonBox, QFont, QFormLayout, QItemSelectionModel,
     QGridLayout, QIcon, QInputDialog, QLabel, QLineEdit, QListWidget, QAbstractItemView,
     QListWidgetItem, QMenu, QPainter, QPixmap, QRadioButton, QScrollArea, QSize,
diff --git a/src/calibre/gui2/tweak_book/function_replace.py b/src/calibre/gui2/tweak_book/function_replace.py
index a51683770b..9133593246 100644
--- a/src/calibre/gui2/tweak_book/function_replace.py
+++ b/src/calibre/gui2/tweak_book/function_replace.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re, io, weakref, sys
 
-from PyQt5.Qt import (
+from qt.core import (
     pyqtSignal, QVBoxLayout, QHBoxLayout, QPlainTextEdit, QLabel, QFontMetrics,
     QSize, Qt, QApplication, QIcon, QDialogButtonBox)
 
diff --git a/src/calibre/gui2/tweak_book/job.py b/src/calibre/gui2/tweak_book/job.py
index 51d563ca9c..873bf7284c 100644
--- a/src/calibre/gui2/tweak_book/job.py
+++ b/src/calibre/gui2/tweak_book/job.py
@@ -9,7 +9,7 @@ import time
 from threading import Thread
 from functools import partial
 
-from PyQt5.Qt import (QWidget, QVBoxLayout, QLabel, Qt, QPainter, QBrush, QRect, QApplication, QCursor)
+from qt.core import (QWidget, QVBoxLayout, QLabel, Qt, QPainter, QBrush, QRect, QApplication, QCursor)
 
 from calibre.gui2 import Dispatcher
 from calibre.gui2.progress_indicator import ProgressIndicator
diff --git a/src/calibre/gui2/tweak_book/live_css.py b/src/calibre/gui2/tweak_book/live_css.py
index 08db1aac03..2ec82cf4e0 100644
--- a/src/calibre/gui2/tweak_book/live_css.py
+++ b/src/calibre/gui2/tweak_book/live_css.py
@@ -6,7 +6,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, QTimer, QStackedLayout, QLabel, QScrollArea, QVBoxLayout,
     QPainter, Qt, QPalette, QRect, QSize, QSizePolicy, pyqtSignal,
     QColor, QMenu, QApplication, QIcon, QUrl)
diff --git a/src/calibre/gui2/tweak_book/main.py b/src/calibre/gui2/tweak_book/main.py
index ec8a17ea17..be2e092ecc 100644
--- a/src/calibre/gui2/tweak_book/main.py
+++ b/src/calibre/gui2/tweak_book/main.py
@@ -7,8 +7,8 @@ import os
 import sys
 import time
 
-from PyQt5.Qt import QIcon
-from PyQt5.QtWebEngineCore import QWebEngineUrlScheme
+from qt.core import QIcon
+from qt.webengine import QWebEngineUrlScheme
 
 from calibre.constants import EDITOR_APP_UID, FAKE_PROTOCOL, islinux
 from calibre.ebooks.oeb.polish.check.css import shutdown as shutdown_css_check_pool
diff --git a/src/calibre/gui2/tweak_book/manage_fonts.py b/src/calibre/gui2/tweak_book/manage_fonts.py
index cb7b2d5b32..aba024cb32 100644
--- a/src/calibre/gui2/tweak_book/manage_fonts.py
+++ b/src/calibre/gui2/tweak_book/manage_fonts.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import sys, textwrap
 from io import BytesIO
 
-from PyQt5.Qt import (
+from qt.core import (
     QSplitter, QVBoxLayout, QTableView, QWidget, QLabel, QAbstractTableModel,
     Qt, QTimer, QPushButton, pyqtSignal, QFormLayout, QLineEdit, QIcon, QSize,
     QHBoxLayout, QTextEdit, QApplication, QMessageBox, QAbstractItemView, QDialog, QDialogButtonBox)
diff --git a/src/calibre/gui2/tweak_book/plugin.py b/src/calibre/gui2/tweak_book/plugin.py
index 1e0f5cf9d3..aa5f37aa34 100644
--- a/src/calibre/gui2/tweak_book/plugin.py
+++ b/src/calibre/gui2/tweak_book/plugin.py
@@ -7,7 +7,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import importlib
 import sys
-from PyQt5.Qt import QToolButton
+from qt.core import QToolButton
 
 from calibre import prints
 from calibre.customize.ui import all_edit_book_tool_plugins
diff --git a/src/calibre/gui2/tweak_book/polish.py b/src/calibre/gui2/tweak_book/polish.py
index bd76602af9..5bb5c56bcb 100644
--- a/src/calibre/gui2/tweak_book/polish.py
+++ b/src/calibre/gui2/tweak_book/polish.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import re
 from threading import Thread
 
-from PyQt5.Qt import (
+from qt.core import (
     QTextBrowser, QVBoxLayout, QDialog, QDialogButtonBox, QIcon, QLabel,
     QCheckBox, Qt, QListWidgetItem, QHBoxLayout, QListWidget, QPixmap,
     QSpinBox, QStyledItemDelegate, QSize, QStyle, QPen, QPalette,
diff --git a/src/calibre/gui2/tweak_book/preferences.py b/src/calibre/gui2/tweak_book/preferences.py
index 82042a597c..79a6e562f9 100644
--- a/src/calibre/gui2/tweak_book/preferences.py
+++ b/src/calibre/gui2/tweak_book/preferences.py
@@ -14,7 +14,7 @@ from polyglot.builtins import (
 from itertools import product
 from copy import copy, deepcopy
 
-from PyQt5.Qt import (
+from qt.core import (
     QDialog, QGridLayout, QStackedWidget, QDialogButtonBox, QListWidget,
     QListWidgetItem, QIcon, QWidget, QSize, QFormLayout, Qt, QSpinBox, QListView,
     QCheckBox, pyqtSignal, QDoubleSpinBox, QComboBox, QLabel, QFont, QApplication,
@@ -348,7 +348,7 @@ class PreviewSettings(BasicSettings):  # {{{
         self.setLayout(l)
 
         def default_font(which):
-            from PyQt5.QtWebEngineWidgets import QWebEngineSettings
+            from qt.webengine import QWebEngineSettings
             s = QWebEngineSettings.defaultSettings()
             which = getattr(s, {'serif': 'SerifFont', 'sans': 'SansSerifFont', 'mono': 'FixedFont'}[which])
             return s.fontFamily(which)
diff --git a/src/calibre/gui2/tweak_book/preview.py b/src/calibre/gui2/tweak_book/preview.py
index acd9692222..ccb74c744a 100644
--- a/src/calibre/gui2/tweak_book/preview.py
+++ b/src/calibre/gui2/tweak_book/preview.py
@@ -8,12 +8,12 @@ import textwrap
 import time
 from collections import defaultdict
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QByteArray, QHBoxLayout, QIcon, QLabel, QMenu, QSize, QSizePolicy,
     QStackedLayout, Qt, QTimer, QToolBar, QUrl, QVBoxLayout, QWidget, pyqtSignal
 )
-from PyQt5.QtWebEngineCore import QWebEngineUrlSchemeHandler, QWebEngineUrlRequestJob, QWebEngineUrlRequestInfo
-from PyQt5.QtWebEngineWidgets import (
+from qt.webengine import QWebEngineUrlSchemeHandler, QWebEngineUrlRequestJob, QWebEngineUrlRequestInfo
+from qt.webengine import (
     QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineView, QWebEngineSettings, QWebEngineContextMenuData
 )
 from threading import Thread
diff --git a/src/calibre/gui2/tweak_book/reports.py b/src/calibre/gui2/tweak_book/reports.py
index cd41d4925b..619091e093 100644
--- a/src/calibre/gui2/tweak_book/reports.py
+++ b/src/calibre/gui2/tweak_book/reports.py
@@ -14,7 +14,7 @@ from csv import writer as csv_writer
 from io import StringIO
 
 import regex
-from PyQt5.Qt import (
+from qt.core import (
     QSize, QStackedLayout, QLabel, QVBoxLayout, Qt, QWidget, pyqtSignal,
     QAbstractTableModel, QTableView, QSortFilterProxyModel, QIcon, QListWidget,
     QListWidgetItem, QLineEdit, QStackedWidget, QSplitter, QByteArray, QPixmap,
diff --git a/src/calibre/gui2/tweak_book/save.py b/src/calibre/gui2/tweak_book/save.py
index 2de36fa06c..b6c6472366 100644
--- a/src/calibre/gui2/tweak_book/save.py
+++ b/src/calibre/gui2/tweak_book/save.py
@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import shutil, os, errno
 from threading import Thread
 
-from PyQt5.Qt import (QObject, pyqtSignal, QLabel, QWidget, QHBoxLayout, Qt, QSize)
+from qt.core import (QObject, pyqtSignal, QLabel, QWidget, QHBoxLayout, Qt, QSize)
 
 from calibre.constants import iswindows
 from calibre.ptempfile import PersistentTemporaryFile
diff --git a/src/calibre/gui2/tweak_book/search.py b/src/calibre/gui2/tweak_book/search.py
index 0ad7a6aff2..a5f9e867c0 100644
--- a/src/calibre/gui2/tweak_book/search.py
+++ b/src/calibre/gui2/tweak_book/search.py
@@ -9,7 +9,7 @@ import regex
 import time
 from collections import Counter, OrderedDict
 from functools import partial
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, QAction, QApplication, QCheckBox, QComboBox, QFont, QFrame,
     QGridLayout, QHBoxLayout, QIcon, QItemSelection, QKeySequence, QLabel, QLineEdit,
     QListView, QMenu, QMimeData, QModelIndex, QPushButton, QScrollArea, QSize, QItemSelectionModel,
diff --git a/src/calibre/gui2/tweak_book/spell.py b/src/calibre/gui2/tweak_book/spell.py
index 312fcbe34a..880b9c0b65 100644
--- a/src/calibre/gui2/tweak_book/spell.py
+++ b/src/calibre/gui2/tweak_book/spell.py
@@ -10,7 +10,7 @@ import sys
 from collections import OrderedDict, defaultdict
 from functools import partial
 from itertools import chain
-from PyQt5.Qt import (
+from qt.core import (
     QT_VERSION_STR, QAbstractTableModel, QApplication, QCheckBox, QComboBox, QDialog,
     QDialogButtonBox, QFont, QFormLayout, QGridLayout, QHBoxLayout, QIcon,
     QInputDialog, QKeySequence, QLabel, QLineEdit, QListWidget, QListWidgetItem,
diff --git a/src/calibre/gui2/tweak_book/text_search.py b/src/calibre/gui2/tweak_book/text_search.py
index b1220095d9..f3bf749edb 100644
--- a/src/calibre/gui2/tweak_book/text_search.py
+++ b/src/calibre/gui2/tweak_book/text_search.py
@@ -3,7 +3,7 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, QHBoxLayout, QVBoxLayout, QLabel, QComboBox, QPushButton, QIcon,
     pyqtSignal, QFont, QCheckBox, QSizePolicy
 )
diff --git a/src/calibre/gui2/tweak_book/toc.py b/src/calibre/gui2/tweak_book/toc.py
index b5668145b2..3bd26086ed 100644
--- a/src/calibre/gui2/tweak_book/toc.py
+++ b/src/calibre/gui2/tweak_book/toc.py
@@ -5,7 +5,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QDialog, QDialogButtonBox, QGridLayout, QIcon, QMenu,
     QSize, QStackedWidget, QStyledItemDelegate, Qt, QTimer, QTreeWidget,
     QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal
diff --git a/src/calibre/gui2/tweak_book/ui.py b/src/calibre/gui2/tweak_book/ui.py
index 2c4a554bdd..f6a7b9b595 100644
--- a/src/calibre/gui2/tweak_book/ui.py
+++ b/src/calibre/gui2/tweak_book/ui.py
@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import os
 from functools import partial
 from itertools import product
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QColor, QDockWidget, QEvent, QHBoxLayout, QIcon, QImage,
     QLabel, QMenu, QPalette, QPixmap, QSize, QStackedWidget, Qt, QTabWidget, QTimer,
     QUrl, QVBoxLayout, QWidget, pyqtSignal
diff --git a/src/calibre/gui2/tweak_book/undo.py b/src/calibre/gui2/tweak_book/undo.py
index 7370920551..ebc6546b9e 100644
--- a/src/calibre/gui2/tweak_book/undo.py
+++ b/src/calibre/gui2/tweak_book/undo.py
@@ -7,7 +7,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import shutil
 
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, Qt, QModelIndex, QApplication, QWidget,
     QGridLayout, QListView, QStyledItemDelegate, pyqtSignal, QPushButton, QIcon, QItemSelectionModel)
 
diff --git a/src/calibre/gui2/tweak_book/widgets.py b/src/calibre/gui2/tweak_book/widgets.py
index 31031e312f..b734ac5581 100644
--- a/src/calibre/gui2/tweak_book/widgets.py
+++ b/src/calibre/gui2/tweak_book/widgets.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import os, textwrap, unicodedata
 from collections import OrderedDict
 
-from PyQt5.Qt import (
+from qt.core import (
     QGridLayout, QLabel, QLineEdit, QVBoxLayout, QFormLayout, QHBoxLayout,
     QToolButton, QIcon, QApplication, Qt, QWidget, QPoint, QSizePolicy,
     QPainter, QStaticText, pyqtSignal, QTextOption, QAbstractListModel, QItemSelectionModel,
diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index c4d20d25d7..766035e49a 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -20,7 +20,7 @@ import textwrap
 import time
 from collections import OrderedDict
 from io import BytesIO
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QApplication, QDialog, QFont, QIcon, QMenu, QSystemTrayIcon, Qt, QTimer,
     QUrl, pyqtSignal
 )
diff --git a/src/calibre/gui2/update.py b/src/calibre/gui2/update.py
index c753eae7ba..b5d847aa7a 100644
--- a/src/calibre/gui2/update.py
+++ b/src/calibre/gui2/update.py
@@ -6,7 +6,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import re, ssl, json
 from threading import Thread, Event
 
-from PyQt5.Qt import (QObject, pyqtSignal, Qt, QUrl, QDialog, QGridLayout,
+from qt.core import (QObject, pyqtSignal, Qt, QUrl, QDialog, QGridLayout,
         QLabel, QCheckBox, QDialogButtonBox, QIcon)
 
 from calibre.constants import (__appname__, __version__, iswindows, ismacos,
diff --git a/src/calibre/gui2/viewer/bookmarks.py b/src/calibre/gui2/viewer/bookmarks.py
index c9dc87cae2..66a73916eb 100644
--- a/src/calibre/gui2/viewer/bookmarks.py
+++ b/src/calibre/gui2/viewer/bookmarks.py
@@ -5,7 +5,7 @@
 
 import json
 from operator import itemgetter
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QComboBox, QGridLayout, QHBoxLayout, QIcon, QInputDialog,
     QItemSelectionModel, QLabel, QListWidget, QListWidgetItem, QPushButton, Qt,
     QWidget, pyqtSignal
diff --git a/src/calibre/gui2/viewer/highlights.py b/src/calibre/gui2/viewer/highlights.py
index d7df480e1c..89e9739a6f 100644
--- a/src/calibre/gui2/viewer/highlights.py
+++ b/src/calibre/gui2/viewer/highlights.py
@@ -7,7 +7,7 @@ import math
 from collections import defaultdict
 from functools import lru_cache
 from itertools import chain
-from PyQt5.Qt import (
+from qt.core import (
     QColor, QFont, QHBoxLayout, QIcon, QImage, QItemSelectionModel, QKeySequence,
     QLabel, QMenu, QPainter, QPainterPath, QPixmap, QPushButton, QRect, QSizePolicy,
     Qt, QTextEdit, QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal,
diff --git a/src/calibre/gui2/viewer/lookup.py b/src/calibre/gui2/viewer/lookup.py
index 85bde48206..82f3e6efd2 100644
--- a/src/calibre/gui2/viewer/lookup.py
+++ b/src/calibre/gui2/viewer/lookup.py
@@ -6,12 +6,12 @@
 import os
 import sys
 import textwrap
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QCheckBox, QComboBox, QDialog, QDialogButtonBox, QFormLayout, QAbstractItemView,
     QHBoxLayout, QIcon, QLabel, QLineEdit, QListWidget, QListWidgetItem, QPushButton,
     QSize, Qt, QTimer, QUrl, QVBoxLayout, QWidget, pyqtSignal
 )
-from PyQt5.QtWebEngineWidgets import (
+from qt.webengine import (
     QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineView
 )
 
diff --git a/src/calibre/gui2/viewer/main.py b/src/calibre/gui2/viewer/main.py
index 350494da9e..9694302e65 100644
--- a/src/calibre/gui2/viewer/main.py
+++ b/src/calibre/gui2/viewer/main.py
@@ -6,8 +6,8 @@
 import json
 import os
 import sys
-from PyQt5.Qt import QIcon, QObject, Qt, QTimer, pyqtSignal
-from PyQt5.QtWebEngineCore import QWebEngineUrlScheme
+from qt.core import QIcon, QObject, Qt, QTimer, pyqtSignal
+from qt.webengine import QWebEngineUrlScheme
 from contextlib import closing
 
 from calibre.constants import FAKE_PROTOCOL, VIEWER_APP_UID, islinux
diff --git a/src/calibre/gui2/viewer/overlay.py b/src/calibre/gui2/viewer/overlay.py
index c0f69cc227..cf700c64d0 100644
--- a/src/calibre/gui2/viewer/overlay.py
+++ b/src/calibre/gui2/viewer/overlay.py
@@ -3,7 +3,7 @@
 # License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import QWidget, Qt, QFontInfo, QLabel, QVBoxLayout, QPalette
+from qt.core import QWidget, Qt, QFontInfo, QLabel, QVBoxLayout, QPalette
 
 from calibre.gui2.progress_indicator import ProgressIndicator
 
diff --git a/src/calibre/gui2/viewer/printing.py b/src/calibre/gui2/viewer/printing.py
index e53a967f7e..98d41564df 100644
--- a/src/calibre/gui2/viewer/printing.py
+++ b/src/calibre/gui2/viewer/printing.py
@@ -8,7 +8,7 @@ import subprocess
 import sys
 from threading import Thread
 
-from PyQt5.Qt import (
+from qt.core import (
     QCheckBox, QDoubleSpinBox, QFormLayout, QHBoxLayout, QIcon, QLabel, QDialog,
     QLineEdit, QPageSize, QProgressDialog, QTimer, QToolButton, QVBoxLayout
 )
diff --git a/src/calibre/gui2/viewer/search.py b/src/calibre/gui2/viewer/search.py
index e6df09cd0c..6067dcb640 100644
--- a/src/calibre/gui2/viewer/search.py
+++ b/src/calibre/gui2/viewer/search.py
@@ -5,7 +5,7 @@
 import json
 import regex
 from collections import Counter, OrderedDict
-from PyQt5.Qt import (
+from qt.core import (
     QCheckBox, QComboBox, QFont, QHBoxLayout, QIcon, QLabel, Qt, QToolButton,
     QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal
 )
diff --git a/src/calibre/gui2/viewer/shortcuts.py b/src/calibre/gui2/viewer/shortcuts.py
index 6ed978918f..5d42907ec7 100644
--- a/src/calibre/gui2/viewer/shortcuts.py
+++ b/src/calibre/gui2/viewer/shortcuts.py
@@ -3,7 +3,7 @@
 # License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from PyQt5.Qt import QKeySequence, QMainWindow, Qt
+from qt.core import QKeySequence, QMainWindow, Qt
 
 
 def get_main_window_for(widget):
diff --git a/src/calibre/gui2/viewer/toc.py b/src/calibre/gui2/viewer/toc.py
index ad6f26755e..20d95004b4 100644
--- a/src/calibre/gui2/viewer/toc.py
+++ b/src/calibre/gui2/viewer/toc.py
@@ -6,7 +6,7 @@
 import re
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QFont, QHBoxLayout, QIcon, QMenu, QModelIndex, QStandardItem,
     QStandardItemModel, QStyledItemDelegate, Qt, QToolButton, QToolTip, QTreeView,
     QWidget, pyqtSignal, QEvent
diff --git a/src/calibre/gui2/viewer/toolbars.py b/src/calibre/gui2/viewer/toolbars.py
index df0d5bcea7..07a1c7b081 100644
--- a/src/calibre/gui2/viewer/toolbars.py
+++ b/src/calibre/gui2/viewer/toolbars.py
@@ -6,12 +6,12 @@
 import os
 from functools import partial
 
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QGroupBox, QHBoxLayout, QIcon, QKeySequence, QLabel, QListWidget,
     QListWidgetItem, QMenu, Qt, QToolBar, QToolButton, QVBoxLayout, pyqtSignal, QDialog,
     QAbstractItemView, QDialogButtonBox
 )
-from PyQt5.QtWebEngineWidgets import QWebEnginePage
+from qt.webengine import QWebEnginePage
 
 from calibre.constants import ismacos
 from calibre.gui2 import elided_text
diff --git a/src/calibre/gui2/viewer/tts.py b/src/calibre/gui2/viewer/tts.py
index 349549c306..8e2a181cf8 100644
--- a/src/calibre/gui2/viewer/tts.py
+++ b/src/calibre/gui2/viewer/tts.py
@@ -2,7 +2,7 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
-from PyQt5.Qt import QDialogButtonBox, QObject, QVBoxLayout, pyqtSignal, QDialog
+from qt.core import QDialogButtonBox, QObject, QVBoxLayout, pyqtSignal, QDialog
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.viewer.config import get_pref_group, vprefs
diff --git a/src/calibre/gui2/viewer/ui.py b/src/calibre/gui2/viewer/ui.py
index 029b55ee97..142068340b 100644
--- a/src/calibre/gui2/viewer/ui.py
+++ b/src/calibre/gui2/viewer/ui.py
@@ -9,7 +9,7 @@ import re
 import sys
 from collections import defaultdict, namedtuple
 from hashlib import sha256
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QCursor, QDockWidget, QEvent, QMainWindow, QMenu, QMimeData,
     QModelIndex, QPixmap, Qt, QTimer, QToolBar, QUrl, QVBoxLayout, QWidget,
     pyqtSignal
diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index c5fb33a0e0..2a7faf2913 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -7,15 +7,15 @@ import os
 import shutil
 import sys
 from itertools import count
-from PyQt5.Qt import (
+from qt.core import (
     QT_VERSION, QApplication, QBuffer, QByteArray, QEvent, QFontDatabase, QFontInfo,
     QHBoxLayout, QIODevice, QLocale, QMimeData, QPalette, QSize, Qt, QTimer, QUrl,
     QWidget, pyqtSignal
 )
-from PyQt5.QtWebEngineCore import (
+from qt.webengine import (
     QWebEngineUrlRequestInfo, QWebEngineUrlRequestJob, QWebEngineUrlSchemeHandler
 )
-from PyQt5.QtWebEngineWidgets import (
+from qt.webengine import (
     QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineSettings,
     QWebEngineView
 )
diff --git a/src/calibre/gui2/viewer/widgets.py b/src/calibre/gui2/viewer/widgets.py
index 576a2ae550..3751a1cb9d 100644
--- a/src/calibre/gui2/viewer/widgets.py
+++ b/src/calibre/gui2/viewer/widgets.py
@@ -4,7 +4,7 @@
 
 import re
 
-from PyQt5.Qt import (
+from qt.core import (
     QAction, QFont, QFontMetrics, QStyle, QStyledItemDelegate, Qt, pyqtSignal, QPalette
 )
 
diff --git a/src/calibre/gui2/webengine.py b/src/calibre/gui2/webengine.py
index aea917caaa..b55c8b62e2 100644
--- a/src/calibre/gui2/webengine.py
+++ b/src/calibre/gui2/webengine.py
@@ -5,8 +5,8 @@
 
 import json
 
-from PyQt5.Qt import QObject, Qt, pyqtSignal
-from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineScript, QWebEngineView, QWebEngineSettings
+from qt.core import QObject, Qt, pyqtSignal
+from qt.webengine import QWebEnginePage, QWebEngineScript, QWebEngineView, QWebEngineSettings
 
 from calibre import prints
 from calibre.utils.monotonic import monotonic
@@ -167,7 +167,7 @@ class RestartingWebEngineView(QWebEngineView):
 if __name__ == '__main__':
     from calibre.gui2 import Application
     from calibre.gui2.tweak_book.preview import WebPage
-    from PyQt5.Qt import QMainWindow
+    from qt.core import QMainWindow
     app = Application([])
     view = QWebEngineView()
     page = WebPage(view)
diff --git a/src/calibre/gui2/widgets.py b/src/calibre/gui2/widgets.py
index f2cf65f364..a27c9d2cb7 100644
--- a/src/calibre/gui2/widgets.py
+++ b/src/calibre/gui2/widgets.py
@@ -7,7 +7,7 @@ Miscellaneous widgets used in the GUI
 '''
 import re, os
 
-from PyQt5.Qt import (QIcon, QFont, QLabel, QListWidget, QAction, QEvent,
+from qt.core import (QIcon, QFont, QLabel, QListWidget, QAction, QEvent,
         QListWidgetItem, QTextCharFormat, QApplication, QSyntaxHighlighter,
         QCursor, QColor, QWidget, QPixmap, QSplitterHandle, QToolButton,
         Qt, pyqtSignal, QRegExp, QSize, QSplitter, QPainter, QPageSize, QPrinter,
@@ -1289,7 +1289,7 @@ class PaperSizes(QComboBox):  # {{{
 
 
 if __name__ == '__main__':
-    from PyQt5.Qt import QTextEdit
+    from qt.core import QTextEdit
     app = QApplication([])
     w = QTextEdit()
     s = PythonHighlighter(w)
diff --git a/src/calibre/gui2/widgets2.py b/src/calibre/gui2/widgets2.py
index ca865284be..cc6143e0c3 100644
--- a/src/calibre/gui2/widgets2.py
+++ b/src/calibre/gui2/widgets2.py
@@ -4,7 +4,7 @@
 
 
 import weakref
-from PyQt5.Qt import (
+from qt.core import (
     QApplication, QByteArray, QCalendarWidget, QCheckBox, QColor, QColorDialog, QFrame,
     QComboBox, QDate, QDateTime, QDateTimeEdit, QDialog, QDialogButtonBox, QFont,
     QFontInfo, QFontMetrics, QIcon, QKeySequence, QLabel, QLayout, QMenu, QMimeData,
diff --git a/src/calibre/gui2/win_file_dialogs.py b/src/calibre/gui2/win_file_dialogs.py
index 7952e3fd81..729751c28e 100644
--- a/src/calibre/gui2/win_file_dialogs.py
+++ b/src/calibre/gui2/win_file_dialogs.py
@@ -172,7 +172,7 @@ def run_file_dialog(
     if app_uid:
         data.append(serialize_string('APP_UID', app_uid))
 
-    from PyQt5.Qt import QEventLoop, Qt, pyqtSignal
+    from qt.core import QEventLoop, Qt, pyqtSignal
 
     class Loop(QEventLoop):
 
diff --git a/src/calibre/gui2/wizard/__init__.py b/src/calibre/gui2/wizard/__init__.py
index aa127548d8..122476e351 100644
--- a/src/calibre/gui2/wizard/__init__.py
+++ b/src/calibre/gui2/wizard/__init__.py
@@ -10,7 +10,7 @@ import os
 import re
 import traceback
 from contextlib import closing, suppress
-from PyQt5.Qt import (
+from qt.core import (
     QAbstractListModel, QDir, QIcon, QItemSelection, QItemSelectionModel, Qt,
     QWizard, QWizardPage, pyqtSignal
 )
diff --git a/src/calibre/gui2/wizard/send_email.py b/src/calibre/gui2/wizard/send_email.py
index 442087d92a..9ea2f0c60e 100644
--- a/src/calibre/gui2/wizard/send_email.py
+++ b/src/calibre/gui2/wizard/send_email.py
@@ -10,7 +10,7 @@ import sys
 from functools import partial
 from threading import Thread
 
-from PyQt5.Qt import (
+from qt.core import (
     QWidget, pyqtSignal, QDialog, Qt, QLabel, QLineEdit, QDialogButtonBox,
     QGridLayout, QCheckBox, QIcon, QVBoxLayout, QPushButton, QPlainTextEdit,
     QHBoxLayout)
diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 2f10cd3690..80c3150120 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -772,7 +772,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
                 else:
                     ret = f.read()
                     if as_image:
-                        from PyQt5.Qt import QImage
+                        from qt.core import QImage
                         i = QImage()
                         i.loadFromData(ret)
                         ret = i
diff --git a/src/calibre/linux.py b/src/calibre/linux.py
index 9a8b11db27..ca2118ffc7 100644
--- a/src/calibre/linux.py
+++ b/src/calibre/linux.py
@@ -1301,7 +1301,7 @@ def write_appdata(key, entry, base, translators):
 
 
 def render_img(image, dest, width=128, height=128):
-    from PyQt5.Qt import QImage, Qt
+    from qt.core import QImage, Qt
     img = QImage(I(image)).scaled(width, height, Qt.AspectRatioMode.IgnoreAspectRatio, Qt.TransformationMode.SmoothTransformation)
     img.save(dest)
 
diff --git a/src/calibre/srv/metadata.py b/src/calibre/srv/metadata.py
index dbf875f2fc..2fb329aa79 100644
--- a/src/calibre/srv/metadata.py
+++ b/src/calibre/srv/metadata.py
@@ -567,7 +567,7 @@ def dump_categories_tree(data):
 
 
 def dump_tags_model(m):
-    from PyQt5.Qt import QModelIndex, Qt
+    from qt.core import QModelIndex, Qt
     ans, indent = [], '  '
 
     def dump_node(index, level=-1):
diff --git a/src/calibre/test_build.py b/src/calibre/test_build.py
index 961a86a9dc..e76a4b85c6 100644
--- a/src/calibre/test_build.py
+++ b/src/calibre/test_build.py
@@ -288,7 +288,7 @@ class BuildTest(unittest.TestCase):
     def test_qt(self):
         from PyQt5.QtCore import QTimer
         from PyQt5.QtWidgets import QApplication
-        from PyQt5.QtWebEngineWidgets import QWebEnginePage
+        from qt.webengine import QWebEnginePage
         from PyQt5.QtGui import QImageReader, QFontDatabase
         from PyQt5.QtNetwork import QNetworkAccessManager
         from calibre.utils.img import image_from_data, image_to_data, test
@@ -321,7 +321,7 @@ class BuildTest(unittest.TestCase):
             na = QNetworkAccessManager()
             self.assertTrue(hasattr(na, 'sslErrors'), 'Qt not compiled with openssl')
             if iswindows:
-                from PyQt5.Qt import QtWin
+                from qt.core import QtWin
                 QtWin
             p = QWebEnginePage()
 
diff --git a/src/calibre/utils/open_with/osx.py b/src/calibre/utils/open_with/osx.py
index 930004568c..5dd3f8cc21 100644
--- a/src/calibre/utils/open_with/osx.py
+++ b/src/calibre/utils/open_with/osx.py
@@ -329,7 +329,7 @@ def get_icon(path, pixmap_to_data=None, as_data=False, size=64):
             return
         if not names:
             return
-        from PyQt5.Qt import QImage, Qt
+        from qt.core import QImage, Qt
         names.sort(key=numeric_sort_key)
         for name in names:
             m = re.search(r'(\d+)x\d+', name)
diff --git a/src/calibre/utils/open_with/windows.py b/src/calibre/utils/open_with/windows.py
index 8f12e1b2a6..b63a45a9f9 100644
--- a/src/calibre/utils/open_with/windows.py
+++ b/src/calibre/utils/open_with/windows.py
@@ -7,7 +7,7 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 import sys
-from PyQt5.Qt import QBuffer, QByteArray, QPixmap, Qt, QtWin, QIODevice
+from qt.core import QBuffer, QByteArray, QPixmap, Qt, QtWin, QIODevice
 
 from calibre.gui2 import must_use_qt
 from calibre.utils.winreg.default_programs import split_commandline
diff --git a/src/calibre/utils/rapydscript.py b/src/calibre/utils/rapydscript.py
index 28a03c0b1c..3b84cdcf6b 100644
--- a/src/calibre/utils/rapydscript.py
+++ b/src/calibre/utils/rapydscript.py
@@ -55,8 +55,8 @@ def compiler():
     ans = getattr(compiler, 'ans', None)
     if ans is not None:
         return ans
-    from PyQt5.Qt import QApplication, QEventLoop
-    from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineScript
+    from qt.core import QApplication, QEventLoop
+    from qt.webengine import QWebEnginePage, QWebEngineScript
 
     from calibre import walk
     from calibre.gui2 import must_use_qt
@@ -203,7 +203,7 @@ def module_cache_dir():
 
 
 def ok_to_import_webengine():
-    from PyQt5.Qt import QApplication
+    from qt.core import QApplication
     if QApplication.instance() is None:
         return True
     if 'PyQt5.QtWebEngineWidgets' in sys.modules:
@@ -331,8 +331,8 @@ def atomic_write(base, name, content):
 
 
 def run_rapydscript_tests():
-    from PyQt5.Qt import QApplication, QEventLoop
-    from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineScript
+    from qt.core import QApplication, QEventLoop
+    from qt.webengine import QWebEnginePage, QWebEngineScript
 
     from calibre.gui2 import must_use_qt
     from calibre.gui2.webengine import secure_webengine
diff --git a/src/calibre/utils/speedups.py b/src/calibre/utils/speedups.py
index 9a7cb776d6..503d7d7557 100644
--- a/src/calibre/utils/speedups.py
+++ b/src/calibre/utils/speedups.py
@@ -50,7 +50,7 @@ def svg_path_to_painter_path(d):
 
     :param d: The value of the d attribute of an SVG <path> tag
     '''
-    from PyQt5.Qt import QPainterPath
+    from qt.core import QPainterPath
     cmd = last_cmd = b''
     path = QPainterPath()
     moveto_abs, moveto_rel = b'M', b'm'
diff --git a/src/calibre/utils/wmf/__init__.py b/src/calibre/utils/wmf/__init__.py
index 238c520a16..392fbb0bc6 100644
--- a/src/calibre/utils/wmf/__init__.py
+++ b/src/calibre/utils/wmf/__init__.py
@@ -61,7 +61,7 @@ def create_bmp_from_dib(raw):
 
 
 def to_png(bmp):
-    from PyQt5.Qt import QImage, QByteArray, QBuffer, QIODevice
+    from qt.core import QImage, QByteArray, QBuffer, QIODevice
     i = QImage()
     if not i.loadFromData(bmp):
         raise ValueError('Invalid image data')
diff --git a/src/calibre/web/feeds/recipes/model.py b/src/calibre/web/feeds/recipes/model.py
index 76cacb1046..a1ac0c1fc1 100644
--- a/src/calibre/web/feeds/recipes/model.py
+++ b/src/calibre/web/feeds/recipes/model.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import copy, zipfile
 from functools import total_ordering
 
-from PyQt5.Qt import QAbstractItemModel, Qt, QColor, QFont, QIcon, \
+from qt.core import QAbstractItemModel, Qt, QColor, QFont, QIcon, \
         QModelIndex, pyqtSignal, QPixmap
 
 from calibre.utils.search_query_parser import SearchQueryParser