A semiconductor composition which comprises a soluble polyacene semiconductor and a polymeric semiconducting binder the binder having a permittivity greater than 3.4 at 000 Hz. The charge mobility of the semiconducting binder when measured in a pure state is greater than 10−7 cm2/Vs and more preferably greater than 10−6 cm2/Vs. Organic thin film transistors in which the source and drain electrodes are bridged by the semiconductor composition have desirable properties of reproducibility and charge mobility. The organic semiconducting composition can be applied by solution coating.