Two series of polyimides I-II with methyl-substituted triphenylamine units were prepared from the diamines, 4,4'-diamino-2 '',4 '',6 ''-trimethyltriphenylamine (Me(3)TPA-diamine; 1) and 4,4'-diamino-4 ''-methyltriphenylamine (MeTPA-diamine; 2), and two commercially available tetracarboxylic dianhydrides via a conventional two-step chemical imidization. All the polymers were readily soluble in many polar solvents and showed useful levels of thermal stability associated with high glass transition temperatures (266-340 degrees C) and high char yields (higher than 49% at 800 degrees C in nitrogen). The polymer films showed reversible electrochemistry/electrochromism accompanied by a color change from neutral pale yellow to green oxidized form with good coloration efficiency, switching time, and stability. The CO2 permeability coefficients (P-CO2) and permeability selectivity (P-CO2/P-CH4) for these polyimide membranes were in the range of 34.1-229.2 barrer and 21.3-28.9, respectively. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3637-3646, 2011