We report that the inclusion of nonaromatic 5,5-dimethylcyclopentadiene monomer into a conjugated backbone is an attractive strategy to high performance semiconducting polymers. The use of this monomer enables a room temperature Suzuki copolymerization with a diketopyrrolopyrrole comonomer to afford a highly soluble, high molecular weight material. The resulting low band gap polymer exhibits excellent photo and thermal stability, and despite a large π–π stacking distance of 4.26 Å, it demonstrates excellent performance in thin-film transistor devices.