Tetrathiafulvalene-based organic semiconductor with biphenyl substituents, DBP-TTF (bis(biphenyl)tetrathiafulvalene) is used as an active layer of an organic field-effect transistor. DBP-TTF forms a good thin film on a SiO2 substrate, in which the DBP-TTF molecules are arranged almost perpendicular to the substrate. The field-effect mobility of the thin-film transistor amounts to 0.11 cm(2)V(-1)s(-1).