We report the synthesis, characterization, and application of a novel series of diketopyrrolopyrrole (DPP)-containing quinoidal small molecules as highly efficient n-type organic semiconductors in thin film transistors (TFTs). The first two representatives of these species exhibit maximum electron mobility up to 0.55 cm(2) V-1 s(-1) with current on/current off (I-on/I-off) values of 10(6) for 1 by vapor evaporation, and 0.35 cm(2) V-1 s(-1) with I-on/I-off values of 10(5)-10(6) for 2 by solution process in air, which is the first demonstration of DPP-based small molecules offering only electron transport characteristics in TFT devices. The results indicate that incorporation of a DPP moiety to construct quinoidal architecture is an effective approach to enhance the charge-transport capability.