A naphthalene bisimide (NBI)-based donor-acceptor (D-A) alternating low-band-gap polymer, which is an electron-transporting material, was successfully synthesized by palladium-catalyzed direct arylation. The obtained polymer had a relatively high molecular weight (M-n = 10000, M-w/M-n = 1.63), and H-1 NMR analysis demonstrated that there were no structural defects.