Derived from SCPDT–PDI4, we synthesized FSPthrough directly fusing PDI units with SCPDT-core [129]. FSPexhibited extended p-conjugation and optimized molecular configuration which leads to better photon absorption and moredesirable energy levels. OSCs based on PTB7–Th/FSP achievedPCE up to 8.89% with the photovoltaic properties better thanSCPDT–PDI4-based devices (Table 2).