molecule

A user-sponsored molecular visualization system on an open-source foundation, maintained and distributed by Schrödinger.

a chemically intelligent desktop toolkit built to help you draw, edit, publish, render, import and export your chemical structures and as well as allowing you to convert between various chemical and graphical file formats.

API usage of JChem Base in .NET & MarvinSketch and MarvinView with GUI support in .NET.

ChemAxon.instantjchem