A copolymer of anti-5,15-bis([2',2":5",2"'-terthiophene]-3"-yl)-2,8,12,18-tetra-n-butyl-3,7,13,17-tetramethylporphyrin (1) with 2,2':5'2"-terthiophene (2) was successfully electrosynthesised and was then characterised by cyclic voltammetry, UV-Vis spectroscopy, four-point probe conductivity measurement, and scanning electron microscopy. This novel light harvesting conducting copolymer was then incorporated into photoelectrochemical cells using a liquid electrolyte and tested for photovoltaic responses. The effect of zinc incorporation into the porphyrin cavity was also investigated, and the best device generated an open circuit voltage of 185 mV, short circuit current of 881 muA cm(-2) with a fill factor of 0.36 and energy conversion efficiency of 0.12% under a halogen white light intensity of 500 W m(-2). (C) 2003 Published by Elsevier Ltd.