 Abstract the graphitic carbon nitride, G, C3N4, which is a two-dimensional conjugated polymer has drawn broad interdisciplinary attention as a low-cost, metal-free, and visible light-responsive photocatalyst in the area of environmental remediation. The G, C3N4-based materials have excellent electronic band structures, electron-rich properties, basic surface functionalities, high-physical chemical stabilities, and are earth abundant. This review summarizes the latest progress related to the design and construction of G, C3N4-based materials in their applications including catalysis, sensing, imaging, and white-light emitting diodes. An outlook on possible further developments in G, C3N4-based research for emerging properties and applications is also included. This article was authored by Ai Wu Wang, Chen Dong Wang, Li Fu, and others.