The electrochemical properties of poly(N-ethylpyrrole) (PEPy) and poly(N-methylpyrrole) (PMPy) films in propylene carbonate (PC) solution, where ion transport is anion-specific, has been investigated using the cyclic electrochemical quartz crystal microbalance (EQCM) technique and electrochemical impedance techniques. The type of dopant anion (PF6- vs. ClO4-) used for the film preparation and the N-substituents (ethyl vs. methyl) have profound effects on the solvent transport behavior, charge capacity, and ionic resistance of the films. (C) 2002 Elsevier Science B.V. All rights reserved.