Diketopyrrolopyrrole (DPP)-based conjugated polymer (P(DPP-BDT)) containing benzodithiophene (BDT) was successfully synthesized via Stille coupling reaction. The synthesized polymer shows good solubility in common organic solvents and good self-film-forming properties. The electrical properties of the polymer were evaluated in organic thin film transistors (OTFTs). The TFT made of pristine P(DPP-BDT) film exhibits good carrier mobility of 0.38 similar to 0.40cm(2) V-1 s(-1) (I-on/off = 10(6), V-th = -9V), which is close to the mobility of TFT made of the thermally annealed film.