The electropolymerization of the transition-metal complexes [M(v-tpy)(2)z](n+) (M = Fe-II, Ru-II, Os-II, Cr-III, Co-II, Ni-II; v-tpy = 4＇-vinyl-2,2＇:6＇,2 "-terpyridine) and the redox processes of their electropolymerized films have been investigated in acetonitrile solution using the electrochemical quartz crystal microbalance (EQCM) and admittance measurements of the quartz crystal resonator. From changes in the frequency, polymerization for each of the complexes was found to be initiated by reduction of the ligand (v-tpy) except for [Ni(v-tpy)(2)](3+), where the mechanism appears to involve an ostensibly metal-centered reduction. In all cases, the increase in the resistance parameter of the electrical equivalent circuit of the resonator with potential cycling also indicated polymerization onto the electrode surface. The redox processes of the polymerized [M(v-tpy)(2)](n+) films appear to be of the anion-exchange type with changes in the film morphology. A mechanism for the "charge-trapping" process of a uniform coating of poly-[M(v-tpy)(2)](2+) (M Fe, Ru, Os) is proposed in terms of changes in film morphology.