In this work, we have designed and synthesized a new naphtho[1,2-b:5,6-b′]dithiophene-containing enlarged π-conjugated donor–acceptor (D–A) small molecule, NDT(TTz)2, for use in solution-processed organic photovoltaics. NDT(TTz)2, which contains a thiophene-bridged naphtho[1,2-b:5,6-b′]dithiophene as the central fused core and triphenylamine-flanked thiophene thiazolothiazole as a spacer, was synthesized via sequential Suzuki and Stille coupling reactions. The thermal, physiochemical, and electrochemical properties of NDT(TTz)2 have been evaluated by differential scanning calorimetry, thermogravimetry, UV–Vis spectroscopy, photoluminescence spectroscopy, X-ray diffraction, and cyclic voltammetry. As desired for photovoltaic applications, NDT(TTz)2 possesses good solubility, thermal stability, and a well-ordered, π–π stacked, crystallinity. The optical band gap and HOMO level of NDT(TTz)2 were determined to be 2.0eV and −5.23eV, respectively. In addition to organic thin film transistor studies, application of NDT(TTz)2 to preliminary photovoltaic devices has also been investigated by fabricating solution-processed bulk heterojunction solar cells together with PC71BM in a typical layered device structure, ITO/PEDOT:PSS/NDT(TTz)2:PC71BM/LiF/Al. Without extensive optimization of the device, NDT(TTz)2 in these devices shows a maximum power conversion efficiency of 1.44% under AM 1.5 illumination at a 100mW/cm2 intensity.