Currently,　high‐performance　polymerized　small‐molecule　acceptors　(PSMAs)　based　on　ADA‐type　SMAs　are　still　rare　and　greatly　demanded　for　polymer　solar　cells　(PSCs).　Herein,　two　novel　regioregular　PSMAs　(PW‐Se　and　PS‐Se)　are　designed　and　synthesized　by　using　centrosymmetric　(linear‐shaped)　and　axisymmetric　(banana‐shaped)　ADA‐type　SMAs　as　the　main　building　blocks,　respectively.　It　is　demonstrated　that　photovoltaic　performance　of　the　PSMAs　can　be　significantly　improved　by　optimizing　the　configuration　of　ADA‐type　SMAs.　Compared　to　the　axisymmetric　SMA‐based　polymer　(PS‐Se),　PW‐Se　using　a　centrosymmetric　SMA　as　the　main　building　block　exhibits　better　backbone　coplanarity　thereby　resulting　in　bathochromically　shifted　absorption　with　a　higher　absorption　coefficient,　tighter　interchain　π–π　stacking,　and　more　favorable　blend　film　morphology.　As　a　result,　enhanced　and　more‐balanced　charge　transport,　better　exciton　dissociation,　and　reduced　charge　recombination　are　achieved　for　PW‐Se‐based　devices　with　PM6　as　polymer　donor.　Benefiting　from　these　positive　factors,　the　optimal　PM6:PW‐Se‐based　device　exhibits　a　higher　power　conversion　efficiency　(PCE)　of　15.65%　compared　to　the　PM6:PS‐Se‐based　device　(8.90%).　Furthermore,　incorporation　of　PW‐Se　as　a　third　component　in　the　binary　active　layer　of　PM6:M36　yields　ternary　devices　with　an　outstanding　PCE　of　18.0%,　which　is　the　highest　value　for　PSCs　based　on　ADA‐type　SMAs,　to　the　best　of　the　knowledge.