New donor/acceptor polymers PBDTDPT1 and PBDTDPT2 with alternating benzodithiophene and N-alkylated dioxopyrrolo-thiophene were synthesized. The new polymers had deep HOMO levels of− 5.42 and− 5.44 eV for PBDTDPT1 and PBDTDPT2, respectively. A PBDTDPT2 based BHJ solar cell device achieved a PCE of 4.79% and Voc of 0.91 V.