An Imine Photocyclization as an Alternative to the Pictet-Spengler Reaction for the Synthesis of AzaBenzannulated Perylenediimide Dyes.

AzaBenzannulated perylenediimide (AzaBPDI) dyes were synthesized in high yields via a new reaction sequence involving an imine condensation followed by visible light-induced photocyclization. The large scope and efficiency of this alternative to the Pictet-Spengler reaction are demonstrated, allowing easy preparation of dimeric AzaBPDI as potential non-fullerene acceptors for organic solar cells.