The present invention relates to electrosynthesis of a compact polymeric film of compounds containing a cyclopentenediones skeleton, on carbon electrodes (vitreous carbon, carbon fiber), gold, platinum and similar solid electrodes. The thus obtained permselective layers can be used in the manufacture of electrochemical sensors and can thus provide selectivity thereof. The electrosynthesis is based on polarization of the electrode with constant or cyclically varying potential greater than or equal to 200 mV (vs. Ag/AgCl/3 M KCl) in an aqueous solution of a corresponding cyclopentenediones monomer.