To characterize the doping and electropolymerize a free-standing semiconducting polymer, the technique of electrodeposition at the Interface between Two Immiscible Electrolyte Solutions (ITIES) was used. The potential use of such films for photovoltaic applications led to a 'plain' terthiophene being chosen as the starting monomer in order to have a longer conjugation length. A new design of a 4-electrode cell allowed us to operate at a relatively high potential but where the potential is still low compared with a value that would damage the formed polymer. The doping level is investigated by both cyclic voltammetric and steady state techniques. (c) 2006 Elsevier B.V. All rights reserved.