We describe the synthesis and preliminary photovoltaic performance of a solution-processable organic small-molecule electron donor that consists of dithienyldiketopyrrolopyrrole (DT-DPP) as the core and thienylvinylthiophene (TVT) as the endgroups. The new compound is a crystalline solid with a of approximately 216°C. Cyclic voltammetry indicates that exhibits two quasi-reversible one-electron oxidation waves at ca. 0.68 and 0.90 V versus an reference electrode, respectively, leading to an estimated highest occupied molecular orbital (HOMO) level of about . Introducing the branched 2-hexyldecyl side chain provides with a high solubility in chloroform up to ca. at room temperature. Thermal annealing increases the crystallinity of the as-cast film from chloroform solution, thereby rendering slightly red-shifted charge-transfer absorption maxima. Fitting the space-charge-limited current characteristics of the thermally annealed thin film yields an improved hole mobility of at low voltages versus of the as-cast film. A first characterization of the solar cell [ITO/PEDOT: : ] produces a power conversion efficiency of with , , and , under simulated AM1.5G with an illumination intensity of . It should be noted that the thermal effect on the thin film absorption of does not seem to be completely similar to the molecular donor reported earlier, which bears 6-fluoronaphthyl endgroups.