Electrochemical synthesis of the copolymer of aniline with dithiodianiline, an aniline derivative containing-S-S-links in it,was carried out in 2 M H2SO4 by cyclic voltammetry (CV). In addition, CV was used to evaluate the differences between the electrochemical characteristics associated with growth of the copolymer and polyaniline (PANI). The deposition of copolymeric film was evident from the observed changes in growth rate, redox potentials, and transport mechanisms of deposited films in contrast to PANI. Plausible reaction schemes are proposed on the basis of CV results for the copolymerization. This involves the possible branched structure for the copolymer and corroborated with other characterizations. X-ray photoelectron spectroscopy and scanning electron microscopy were used to determine the nitrogen and sulfur content and the morphological behavior of the copolymer, respectively. The results show that the copolymer possesses a different charge transport mechanism in films and a branched structure as a consequence of incorporation of DTDA units resulting in -S-S- links in the polyaniline structure. (C) 2001 The Electrochemical Society. All rights reserved.