The electrochemical performance of polyaniline thin films on platinum electrode substrates has been investigated using cyclic voltammetry in two aprotic ionic liquid electrolyte systems, 1-butyl-3-methyl imidazolium hexafluorophosphate (BMI PF6-) or 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfon)imide (EMI TFSI). Enhanced redox stability of the polyaniline was observed in both electrolyte systems. Initial redox cycles in both ILs exhibited increasing current responses, over the first 10-20 cycles, which was attributed to the electrochemically induced ion exchange processes occurring within polyaniline film. Extended cycling after the redoping process was observed to result in a stable and reversible electrochemistry. (C) 2003 Elsevier B.V. All rights reserved.