Intramolecular charge transfer (ICT) derived from a donor-acceptor system has been applied for years to enhance the charge mobility in the field of organic photovoltaics and chemical sensing.Similar strategies have gradually been developed in polymeric graphitic carbon nitride (GCN) photocatalytic systems for promoting the light absorption and charge separa-tion.However,there are no reviews focusing on the effects of ICT after the modification of GCN so far.Herein,we summarize some typical literature on GCN engineering to expound profoundly the roles of ICT in electronic properties regulation in terms of in-situ formation and molecular coupling.At last,some important perspectives are also proposed.This review will deepen understanding of the traditional theory for a new recognition among such many methods to improve the performance of GCN.