Self assembled monolayer field effect transistors (SAMFETs) are reported using a phenylene-thiophene containing semiconducting mesogen attached through a trichlorosilane anchoring group. Monolayer films, covalently attached to silicon dioxide substrates, form in less than 10 h from solution, thanks to the accelerated reaction of the trichlorosilane anchor. Devices exhibit mobilities as high as 1.7 x 10(-2) cm(2) V-1 s(-1), currents of up to 15 A (on/off current ratio of 10(6)) with device yields close to unity over large areas for channel lengths up to 100 m.