The sorption of the light gases CH4, N-2, CO2 as well as water into polymer films prepared from a commercial sample of 3,3'-4, 4'-benzophenone tetracarboxylicdianhydride diaminophenylindane (Matrimid 5218) are measured. The light gas isotherms follow standard dual-sorption behavior for polymeric films with the Henry's Law coefficient correlated to the Lennard-Jones well depth parameter. Water sorption behavior was similar to rubbery polymers, that of significant adsorption into the polymeric matrix and was modeled by Henry's law exclusively. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2284-2289, 2010