The key challenge of the photocatalytic technology is to discover a low-cost photocatalyst with the functions of efficient sunlight utilization and high charge separation rate for application in the field of renewable energy generation. Graphitic carbon nitride (g-C₃N₄) has spurred worldwide attention due to its abundance of raw materials, superior visible-light response activity, facile synthetic strategy, chemical stability, and a unique layered structure. In the past decade, the combination of g-C₃N₄ and organic compounds became a research hotspot because of its low cost, adjustable solar light absorption band and stable crystal structures. In this review, (1) the latest developments in the morphology control of g-C₃N₄ as a photocatalyst including nanorods, nanotubes, nanosheets, nanospheres, porous structures and other different tunable nanostructures, are systematically studied. (2) The incorporation strategies of g-C₃N₄ with various organic compounds including recently reported organic molecules, polymers and metal–organic frameworks (MOFs) with the aim of improving the overall photocatalytic performance are discussed in detail. (3) We theoretically present applications in water splitting, CO₂ reduction, pollutant degradation and environmental disinfection. Finally, the research challenges and prospects of organic compound composited g-C₃N₄ towards hydrogen evolution through water splitting are proposed.