PenzeneΒΆ

An open-source, native desktop chemical structure editor, and a free alternative to ChemDraw. It runs on macOS, Linux and Windows, and does its chemistry with RDKit.

Penzene with aspirin Penzene with aspirin, dark theme

New to Penzene? Start with Your first molecule in five minutes. The tutorials then walk through drawing caffeine with the keyboard, reaction schemes and rendering a whole dataset from Python.

The same drawing from a script:

penzene --render "CC(=O)Oc1ccccc1C(=O)O" aspirin.svg

Draw fast

With the mouse or the keyboard: point at an atom and type 2 for a carbonyl or a for a phenyl.

Chemistry built in

Live formula and mass, stereo labels, a properties panel, structure checks, and names from PubChem.

Figures for papers

ACS, RSC and JDP styles, reaction schemes, electron-pushing arrows, templates, and exports that reopen as editable drawings.

Works with ChemDraw

Open and save CDXML and CDX, and paste from ChemDraw.

Scriptable

The same engine from Python and the command line.

Free and open

GPL-3.0, with the source on GitHub.

Start with Installing, then Drawing.