The MLREM model significantly underestimated the experimental values for Φ prediction while the BRANNLP model grossly overestimated them (Table and Table ). This is undoubtedly because the Φ values for some new polymers lie outside the domain of the training data used to generate the model. Higher experimental Φ values measured in all NDI-copolymers should be due to the moderate packing between the donor and acceptor groups, which is mediated by the styrenic groups in the polymer backbone. Meanwhile, the styrenic matrix may facilitate the charge transfer processes by providing a π-electron rich environment. Consequently, the copolymerization strategy can reduce the emission-suppressing effect of charge transfer in NDI copolymers.