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Chemical Drawing Atlas

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PyChem-Pro

A desktop chemistry application and Python library for molecular visualization, structure sketching, geometry optimization, and cheminformatics.

WebsiteManualGitHub

Source available. 28 of 65 checklist features confirmed.

Main canvas

PyChem-Pro main canvas, light mode
light mode
PyChem-Pro main canvas, dark mode
dark mode

Canvas stays white; Light leaves dark toolbars with low contrast.

Default drawings

caffeine as drawn by PyChem-Pro with default settings

Caffeine

paclitaxel as drawn by PyChem-Pro with default settings

Paclitaxel

cholesterol as drawn by PyChem-Pro with default settings

Cholesterol in 3D

Facts

GitHub stars
401 stars on 6 Nov 2026
First commit
18 Mar 2026
Repository activity
292 commits, 4 contributors, last push 18 Oct 2026
Latest version
v1.0.0
Version we tested
1.0.0
Runs on
macOS, Windows, Linux
License
Custom noncommercial terms labeled PolyForm; service use restricted; bundled OASA has separate GPL notices.
Price
Free for personal and educational use (2026-11-05); commercial use prohibited.
Relies on
ChemCanvas, OASA. 2D sketcher files are marked "Adapted from ChemCanvas (GPLv3)". OASA is vendored and credited in the README.
Draws with
Qt QPainter for molecular views and raster exports; Qt QGraphicsScene sketcher; offline ray-tracing export.
Chemistry from
In-house Python/NumPy chemistry with vendored OASA for SMILES and 2D layout; optional RDKit plugin.
Interface
PySide6 (Qt 6).
Main language
Python
Other languages
None
Renderer
Borrowed: Adapted ChemCanvas sketcher; in-house QPainter views
Third-party licenses
Includes GPL-3.0-or-later (ChemCanvas), GPL-2.0-or-later (OASA), LGPL-2.1 (Jmol data), and LGPL-3.0/GPL-3.0 or commercial terms (PySide6/Qt).
Download
1.6 MB
Installed
1.6 GB

In use

Screenshots from our test of this version.

Features

  • Tested by running it
  • Seen in the app
  • The manual says yes
  • Partly, with the reason shown
  • Not supported
  • Not established, which is not the same as no

Select a mark for its proof. A filled mark opens our screenshot, or the manual if the check left nothing to picture. A ring opens the manual.

Drawing structures

Figures and layout

Open the full pageManual