Organic thin film transistors (TFTs) have been fabricated using thermally evaporated films of the oligophenylsp-quaterphenyl (p-4P),p-quinquephenyl (p-5P), andp-sexiphenyl (p-6P). The field-effect mobility of these TFTs ranges from10−2 cm2/V sforp-4P to10−1 cm2/V sforp-6P with on/off current ratio from105to106.These values are comparable to those achieved using the more widely studied organic semiconductors alpha-sexithienyl (&agr;-6T) and pentacene. X-ray diffraction reveals a high degree of molecular ordering, believed to be important for obtaining high field-effect mobility in organic TFTs. ©1997 American Institute of Physics.