AbstractDouble‐cable conjugated polymers with pendent electron acceptors, including fullerene, rylene diimides, and nonfused acceptors, have been developed for application in single‐component organic solar cells (SCOSCs) with efficiencies approaching 10%. In this work, Y‐series electron acceptors have been firstly incorporated into double‐cable polymers in order to further improve the efficiencies of SCOSCs. A highly crystalline Y‐series acceptor based on quinoxaline core and the random copolymerized strategy are used to optimize the ambipolar charge transport and the nanophase separation of the double‐cable polymers. As a result, an efficiency of 13.02% is obtained in the random double‐cable polymer, representing the highest performance in SCOSCs, while the regular double‐cable polymer only provides a low efficiency of 2.75%. The significantly enhanced efficiencies are attributed to higher charge carrier mobilities, better ordering conjugated backbones and Y‐series acceptors in random double‐cable polymers.