A novel synthetic strategy for efficient construction of dragon-boat-type heptathienoacenes (DBHTs) via the α-β position carbon-carbon cross-coupling between two dithienothiophenes is employed. Their crystal structures are confirmed by X-ray single-crystal analysis. The first thin film FET devices of heptathienoacenes are fabricated using OTS-treated SiO2/Si substrates, in which DBHT-5-based devices exhibit an unprecedented highest hole mobility value of 1.15 cm2 V-1 s-1 and on/off ratios over 106 with a threshold voltage of 0 V.