Six phenyl-flanked benzodipyrrolidone-based copolymers are designed, synthesised and characterised. Three exhibit backbone in-plane curvature or out-of-plane twisting, while the other three remain planar and co-linear. While the first three appear less crystalline by X-ray diffraction, they afford a smoother solid-state film surface topology and increased electron mobility in top-gate, bottom-contact OFETs.