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The past 5 years have witnessed the rapid development of organic solar cells based on nonfullerene acceptors (NFAs) [1-26].The state-of-the-art NFA-based single-junction and tandem solar cells afforded 18.22％ (certified 17.6％) and 17.36％ (certified 17.29％) power conversion efficiencies (PCEs), respectively [27,28].Wide-bandgap (WBG) polymer donors are ideal partners for NFAs.They present complementary absorption with that of low-bandgap NFAs and deep the highest occupied molecular orbital (HOMO) levels.Therefore, solar cells based on a WBG polymer and a NFA can generate high short-circuit current density (JSC) and open-circuit voltage (VOC) [29].Meanwhile, some WBG polymers show high crystallinity and mobility, gifting the solar cells high fill factors (FF) [30].Recently, our group first reported efficient WBG D-A copolymer donors based on fused-ring aromatic lactone (FRAL) acceptor units.Thanks to the strong electron-withdrawing capability and extended molecular plane of FRAL units, these polymers show deep HOMO levels, high crystallinity and good hole mobility, delivering high PCEs in nonfullerene solar cells [31,32].