A copolymer of 5,15- bis([2'2":5",2'''-terthiophen]-3"-yl)-2,8,12,18-tetra-n-butyl-3,7,13,17-tetramethylporphyr in with 2,2':5'2"-terthiophene was successfully electrosynthesized by cyclic voltammetry, galvanostatic, and potentiostaic methods. This conducting copolymer was then incorporated into photovoltaic devices using liquid electrolyte and tested for photovoltaic responses. An ionic liquid, ethyl-methylimidazolium dicyanamide, containing iodine (I-2, 60 mM) and tetrapropylammonium iodide (TPAI, 500 mM) has been employed as liquid electrolyte in photoelectrochemical solar cells based on polyterthiophenes containing porphyrins with an overall conversion efficiency of 0.14 % at a solar simulated light intensity of 500 W m(-2). (c) 2005 The Electrochemical Society.