C70-based acceptors show great potential in polymer solar cells (PSCs). Two high-LUMO C70 acceptors, the 66π OQMF70 and the 64π bis-OQMF70, based on methano[70]fullerene (C70CH2) were developed. An outstanding power conversion efficiency (PCE) of 6.88% was obtained from OQMF70:P3HT solar cells.