We　report　two　new　regioregular　and　regioirregular　model　copolymer　acceptors　based　on　selenophene　and　perylenetetracarboxylic　diimide　moieties,　respectively,　named　RR-P(SePDI)　and　RI-P(SePDI),　which　were　synthesized　to　study　how　regioregularity　impacts　the　properties　of　resulting　polymers.　The　structural　regioregularity　impact　on　the　performance　of　polymer-polymer　solar　cells　(PPSCs)　was　highlighted.　Both　the　copolymer　acceptors　displayed　similar　optoelectronic　properties.　The　regioregular　RR-P(SePDI)　exhibited　better　and　balance　bulk　charge-transport　capability　than　regioirregular　RI-P(SePDI)　in　active　layer　films.　The　typical　PPSCs　based　on　the　regioirregular　RI-P(SePDI)　copolymer　acceptor　and　the　PTB7-Th　polymer　donor　afforded　average　power　conversion　efficiencies　(PCEs)　of　about　5.3%.　Importantly,　reasonably　improved　average　PCEs　of　about　6.2%　were　provided　by　the　blend　active　layer　of　new　regioregular　RR-P(SePDI)　and　PTB7-Th.　These　results　highlight　the　significant　and　efficient　strategy　of　rational　control　regioregularity　of　the　polymer　backbone　to　gain　high　PCE　values　in　perylene　diimide-based　PPSCs.　©　2018　American　Chemical　Society.