a new metal-free ternary composites based on organic molecular, N doped graphene quantum dots (N-GQDs) and g-C3N4 was developed. The photocatalytic activity was evaluated for photocatalytic degradation of organic pollutant. It showed high photocatalytic degradation rate (ca. 0.25 mg/min) and ultra-short photocatalytic time (ca. 3.0 min) for complete degradation of organic dye (eg, RhB) in water. The enhanced photocatalytic performance was attributed to the synergistic effect of organic molecule and graphene quantum dots, enhancing visible light absorption, suppressing recombination of photogenerated charges and accelerating photoredox reaction of g-C3N4. The study did not only propose a facile method to synthesis of free-metal photocatalysts with ultra-fast photocatalytic rate, but also represented a new method to improve the photocatalytic activity of photocatalysts based on carbon materials.