The electropolymerization of bithiophene on aluminum electrodes was studied in acetonitrile in the presence of lithium perchlorate as the doping agent; the film formation was achieved under potential control. To restrain metal electro-oxidation and dissolution, the aluminum surfaces were chemically modified with thiols CH3(CH2)(9)-SH and phi-(CH2)(m)-SH; m = 0 to 3 prior to electropolymerization. It was observed that pretreatment with the mercaptan molecules generally limited the electro-oxidation of the metallic electrode while still allowing the bithiophene electropolymerization. Both the electrochemical and morphological properties of these polybithiophene films were improved as compared with those prepared on the bare metal: Adhesion of polybithiophene to the substrate is drastically enhanced in the case of phi-(CH2)(m)-SH.