There have been many reports on the application of pyrene derivatives as organic semiconductors, but 1,8subsituted pyrene semiconductors are less well-developed. Twop -type 1,8-substituted pyrene derivatives were synthesized that were composed of apyrene core, thiopheneorb ithiophene arms, and end-capped octyl chains.T hese structures weren ot completely symmetrical and the dihedral angles between the pyrene core and the adjacent thiophene units had ad ifferenceo fapproximately two degrees. The field-effect performance of these materials was tested on a variety of dielectric surfaces. The performance of both materials with as pin-coated polystyrene layer on SiO 2 (PS-treated SiO 2 )w as better than that with an octadecyltrichlorosilane self-assembled monolayer on SiO 2 (OTS-treated SiO 2 ), which was mainly attributed to the presence of large grains on the low-leakage and high-capacitance PS films. The thiophenecontained compound presented ah ole mobility of up to 0.18 cm 2 V À1 s À1 on PS-treated SiO 2 ,w hich was 45 times that of the bithiophene-contained compound, owing to less steric hindrance, high crystallinity,and largegrain size.