Detailed characterization of low molecular weight byproducts of oxidative polymerization of aniline is given. Presence of these compounds in the final product of polymerization strongly influences its macroscopic properties, such as density, solubility, etc., and they should be removed for the sake of reproducibility of properties of the polymer. We focused our research on separation and identification of the low molecular weight compounds, which are created during the polymerization process. We also compared the results obtained for room temperature and 0degreesC polymerization products. Polymerization at -30degreesC was also carried out but only very small amounts of the low molecular weight products were produced. (C) 2004 Elsevier Ltd. All rights reserved.