Thin-film transistors (TFTs) based on a new n-channel organic semiconductor (DCMT; see Figure) are reported. An electron mobility as high as 0.2 cm(2)/V s was observed, as well as ambipolar TFT behavior. Variable temperature measurements reveal that electron conduction is activated, with a small activation energy of 35 +/- 10 meV These results demonstrate that quinoidal oligothiophenes are a promising new class of organic semiconductors for TFTs.