Facile one-pot [1 + 1 + 2] and [2 + 1 + 1] syntheses of thieno[3,2-b]thieno[2',3':4,5]thieno[2,3-d]thiophene (tetrathienoacene; TTA) semiconductors are described which enable the efficient realization of a new TTA-based series for organic thin-film transistors (OTFTs). For the perfluorophenyl end-functionalized derivative DFP-TTA, the molecular structure is determined by single-crystal X-ray diffraction. This material exhibits n-channel transport with a mobility as high as 0.30 cm(2)V(-1)s(-1) and a high on-off ratio of 1.8 x 10(7). Thus, DFP-TTA has one of the highest electron mobilities of any fused thiophene semiconductor yet discovered. For the phenyl-substituted analogue, DP-TTA, p-channel transport is observed with a mobility as high as 0.21 cm(2)V(-1)s(-1). For the 2-benzothiazolyl (BS-) containing derivative, DBS-TTA, p-channel transport is still exhibited with a hole mobility close to 2 x 10(-3) cm(2)V(-1)s(-1). Within this family, carrier mobility magnitudes are strongly dependent on the semiconductor growth conditions and the gate dielectric surface treatment.