Conductive polymers having repeating units of formula (II) ##STR1## formed by chemical or electrochemical oxidation of aniline derivatives of formula (I) ##STR2## wherein R.sub.1 denotes --(CH.sub.2).sub.n --; n is an integer between 2 and 12; R.sub.2, R.sub.3, R.sub.4 and R.sub.5 denote hydrogens or one or two of them can be a halogen atom, methyl, methoxy or nitro groups; and X denotes hydrogen an alkali metal ion, an ammonium ion, an alkyl ammonium ion or an anilinium ion. The conductive polymers have excellent stability toward electrochemical redox cyclization and good processibility.