Films of polydiphenylamine-BF4- anion (PDPA-BF4) synthesized electrochemically in neutral and acid nonaqueous media were electrochemically modified by iodide species in HClO4 aqueous media containing I- ions. Raman and FT-IR spectroscopies were used to identify the chemical species in the system PDPA-I-X(-). A significant increase in the conductivity was observed for PDPA due to interaction with iodide species. In this work, we have used a dimer compound approach for the understanding of the vibrational spectra of the principal forms of polydiphenylamine-dopant. The frequencies observed were associated to the stabilization of diphenylbenzidine radical cation (DPB+.) and dication (DPB2+) species of the N,N-diphenylbenzidine (DPB) in the polymeric structure. (C) 2003 Elsevier B.V. All rights reserved.