diff --git a/avogadro/qtplugins/spectra/CMakeLists.txt b/avogadro/qtplugins/spectra/CMakeLists.txt
index 0bba92cf24..b9b77013d7 100644
--- a/avogadro/qtplugins/spectra/CMakeLists.txt
+++ b/avogadro/qtplugins/spectra/CMakeLists.txt
@@ -13,4 +13,7 @@ avogadro_plugin(Spectra
   "vibrationdialog.ui"
 )
 
-target_link_libraries(Spectra PRIVATE Avogadro::Vtk)
+if (USE_VTK)
+  add_definitions(-DUSE_VTK)
+  target_link_libraries(Spectra PRIVATE Avogadro::Vtk)
+endif()
diff --git a/avogadro/qtplugins/spectra/spectra.cpp b/avogadro/qtplugins/spectra/spectra.cpp
index bdf87d116f..8779e197fc 100644
--- a/avogadro/qtplugins/spectra/spectra.cpp
+++ b/avogadro/qtplugins/spectra/spectra.cpp
@@ -238,6 +238,7 @@ void Spectra::openDialog()
   m_dialog->show();
 }
 
+#ifdef USE_VTK
 void Spectra::showSpectraChart()
 {
   if (m_molecule == nullptr || m_molecule->vibrationFrequencies().empty())
@@ -294,6 +295,7 @@ chart->setXAxisLimits(4000.0, 0.0);
 chart->setYAxisLimits(maxIntensity, 0.0);
 m_chartDialog->show();
 }
+#endif
 
 void Spectra::advanceFrame()
 {
diff --git a/avogadro/qtplugins/spectra/spectra.h b/avogadro/qtplugins/spectra/spectra.h
index 840678d137..f3c53224f8 100644
--- a/avogadro/qtplugins/spectra/spectra.h
+++ b/avogadro/qtplugins/spectra/spectra.h
@@ -69,7 +69,9 @@ private slots:
   QtGui::Molecule* m_molecule;
 
   VibrationDialog* m_dialog;
+#ifdef USE_VTK
   QScopedPointer<VTK::ChartDialog> m_chartDialog;
+#endif
 
   QTimer* m_timer;
 
diff --git a/avogadro/vtk/chartwidget.cpp b/avogadro/vtk/chartwidget.cpp
index 168b074777..bc6ac306d6 100644
--- a/avogadro/vtk/chartwidget.cpp
+++ b/avogadro/vtk/chartwidget.cpp
@@ -123,8 +123,6 @@ void ChartWidget::setXAxisTitle(const std::string title)
   axis->GetTitleProperties()->SetFontSize(18);
   axis->GetTitleProperties()->SetBold(true);
 
-  qDebug() << " chart font " << axis->GetTitleProperties()->GetFontFamilyAsString();
-
   axis->GetLabelProperties()->SetFontSize(14);
 }