Meso-tetra-(4-sulfonatophenyl)-porphin (TPPS4) has been incorporated into polypyrrole (PPy) films as a dopant-anion during elect ropolymerisation from aqueous solutions. The addition of TPPS4 to the polymerisation solution increases the rate of electropolymerisation substantially, changes the morphology markedly, and increases the redox-activity of the PPy films formed. This catalytic effect of the TPPS4 on the rate of electropolymerisation was established in the case of non-metallized porphyrin; it means that the effect is not caused by the influence of redox-active metal-ions inserted into the porphin centre. Insertion of the Co2+ ions into the porphin centres was carried out from acetate solutions with high efficiency (70%) even in the case of thick (3-10 mum) TPPS4 doped PPy films. Well-developed waves connected with the Co2+/3+ transition taking place in meso-tetra-(4-sulfonatophenyl)-porphyrinato cobalt (11) (CoTPPS4) were established. The voltammograms measured in an air atmosphere show that the electrocatalytic reduction of molecular oxygen starts at the same potential as the wave of Co redox-transition. The PPy films have been characterised by cyclic voltammetry, SEM, AFM, and X-ray microanalysis. (C) 2004 Elsevier B.V. All rights reserved.