Electropolymerization of aniline in the presence of neutral red was carried out by using repeated potential cycling between -0.20 and 1.00 V (versus Ag/AgCl with saturated KCl solution) on a platinum foil from 0.3 mol dm(-3) H2SO4 solution at room temperature. The experiments of the rotating ring-disk electrode show that an intermediate is generated during electrolysis of aniline and the mixture of aniline and neutral red, respectively. Neutral red can increase the polymerization rate of aniline. The coelectropolymerization of aniline and neutral red is verified from the results of UV-visible spectra, FTIR spectra and XPS spectra of the polymers. The conductivity of the copolymer is one to two orders of magnitude higher than that of polyaniline synthesized under the same conditions but in the absence of neutral red. The electrochemical propel-ties of the copolymer are mainly attributed to polyaniline. (c) 2006 Elsevier B.V. All rights reserved.