Most functionalized thiophenes are difficult to electropolymerize due to nucleophilicity that will attack the radical cation inhibiting polymerization. However, we have successfully electrodeposited a newly synthesized functionalized terthiophene monomer 3-((2':2 '',5 '':2'''-terthiophene)-3"-yi) acrylic acid (TAA) as an active layer of a organic field-effect transistor (OFET). The polymer was then oxidized in order to increase its conductivity. Various oxidizing potentials were experimented and their effect on the OFET's charge mobility was examined. A mobility of 0.25 cm(2) (V s)(-1) is achieved with an oxidizing potential of 0.9 V after vacuum drying. (c) 2008 Elsevier B.V. All rights reserved.