We present a solution processed organic field-effect transistor based on a benzothiadiazole (BTZ)cyclopentadithiophene (CDT) copolymer with mobilities as high as 0.17 cm(2)/Vs and an on/off ratio of 10(5). This pronounced performance together with the lack of macroscopic order in the thin film makes this conjugated copolymer an attractive candidate for low-cost organic electronics due to its facile processing.