The structure of stable polyfurane films doped with perchlorate anions (PFu/ClO4), electrogenerated at constant deposition overpotential, has been studied by FTIR spectroscopy. Electropolymerization overpotential, and monomer/electrolyte concentration ratio were the variables analyzed in this study as a mean of determining the synthesis conditions that would best produce more aromatic polymers (which would imply a larger extended pi-conjugated system). The spectra revealed a clear influence of both variables on the films generated, and although ring opening was detected, justified by the existence of aliphatic CH, OH, and C=O stretching vibrations, the spectra of these electroactive films showed higher aromaticity than had been previously reported by others authors. To study the aromaticity level and ring rupture of the PFu/ClO4 films, the experimental profile of the 1829-1345 cm(-1) FTIR region was fitted to theoretical function, and the resulting three bands were assigned and analyzed as a function of the synthesis conditions.