Electrooxidative polymerization of aromatic compounds such as pyrrole, thiophene and aniline was carried out in air-and moisture-stable ionic liquid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMICF3SO3). The polymerization rate and morphological structure of polymer films formed on the anode were affected, and the electroconductivity was significantly increased. Furthermore, the polypyrrole film prepared in EMICF3SO3 was applied to a matrix for hosting catalyst particles electrodeposited. (C) 2003 Elsevier B.V. All rights reserved.