Polypyrrole and 5 substituted polythiophenes were synthesized by electrochem. polymerization of resp. monomers (cyclic voltammetry in [Bu4N+][BF4-] electrolyte) and deposited on medical steel and electrodes. Nanoporous polymer layers (thickness up to 214 mu m) were produced and recommended for solid phase microextn. The film thickness increased with increasing the cycle no.