Mono- and disilanylene-bridged oligothiophenes were synthesized and their TFT properties were investigated as p-type 4-semiconductors. Among them, the best TFT performance was achieved by using bis(ethylquinquethienyl)dibutylsilane as the active compound whose mobility and on/off ratio were determined to be 2.2 x 10(-2) cm(2) V-1 s(-1) and 10(5), respectively.