Electrochemical copolymerization of aniline (ANI) with dithiodianiline (DTDA), an aniline derivative containing -S-S- links was carried out in 2M H 2 SO 4 using cyclic voltammetry. The cyclicvoltamogram (CV) of the deposited copolymer was recorded in monomer free background electrolyte. A close comparison of the CV characteristics of the films deposited during polymerization of mixture of ANI and DTDA clearly the copolymer deposition. The UV-VIS spectroscopy, spectroelectrochemical studies, thermal analysis and FTIR spectroscopic analysis were used to identify the differences between the copolymer and PANI in the optical, thermal properties and structure. The copolymer was found to have a branched structure in comparison with PANI. The copolymer exhibit different colors upon changing applied potentials.