Title: Use of PyMOL with OpenEye Scientific Software Author: Warren L. DeLano DeLano Scientific LLC Abstract: PyMOL is a molecular viewer application, based on an open source foundation, but that is commercially supported by DeLano Scientific LLC via annual subscriptions. The company has chosen to market PyMOL in such as way as to enable everyone to begin deriving value from it without first having to clear significant financial hurdles. Also, since PyMOL is an open-source, Python-enabled software package, PyMOL users have both the freedom and the means by which to integrate, customize, or extend the program to suit their unique needs. Because of these characteristics, PyMOL is rapidly becoming a ubiquitous molecular visualization tool in industry and academia, with heavy usage in computational chemistry, structural biology, and for presentation graphics. Here we explore how PyMOL's utility can be significantly enhanced by drawing upon the power of OpenEye Scientific Software toolkits. By combining OpenEye's high-value proprietary software with DeLano Scientific's relatively generic open-source solution, users can draw upon the relative strengths of both proprietary and non-proprietary approaches in meeting their various molecular modeling and visualization needs.