The electrochemical oxidation of neutral red in 0.5 mol dm(-3) sulfuric acid and 0.2 mol dm(-3) ferrocenesulfonic acid solution was carried out using repeated potential cycling between -0.20 and 1.40 V (versus SCE). The polymer film was electrochemically deposited on a platinum anode and had an electrochemical activity in the solution of 0.5 mol dm(-3) Na2SO4 with pH <= 7.0. The result from the X-ray photoelectron spectroscopy (XPS) experiment shows that the anions can be doped into the polymer film during the electrochemical polymerization reaction of neutral red. The scanning electron microscopy (SEM) micrograph shows that the surface of the resulting polymer film formed on the platinum foil is covered with a compact surface consisting of micro fibers. The visible spectrum and infrared spectrum (IR) of the polymer are different from those of the corresponding monomer. A possible chemical structure of the resulting polymer was also proposed. (C) 2007 Elsevier Ltd. All rights reserved.