The Chemistry Development Kit (CDK) is a library of Java classes for chemo-, bioinformatics, computational chemistry, and chemometrics. It provides important algorithms like substructure search, SMILES, Gasteiger charges, QSAR descriptor calculation, 3D structure generation, 2D layout and rendering, many IO formats, atom typing, and more.
libmng-py is a Python wrapper around the libmng C library. It currently supports the most important parts of the library, and supports displaying and usage with the most popular toolkits (such as pygame and wxPython). It runs on Mac OS X, Linux, and Windows on all architectures on which ctypes also runs.