Graphitic carbon nitride-supported L-arginine (g-C3N4@L-arginine) has been prepared as a heterogeneous catalyst for synthesizing heterocyclic compounds such as pyranopyrazole and acridinedione derivatives. High efficiency, short reaction time, and easy separation are major assets for using g-C3N4@L-arginine as a catalyst in one-pot multicomponent reactions. Numerous analyses were used to detect synthesized compounds such as FE-SEM (Field Emission Scanning Electron Microscopy), EDX (Energy Dispersive X-ray spectroscopy), XRD (X-Ray Diffraction analysis), TGA (Thermo Gravimetric Analysis), and FT-IR (Fourier Transform Infrared Spectroscopy). g-C3N4@L-arginine nanocatalyst was reused five times in the reaction with no apparent decrease in reaction yield, which shows acceptable recyclability.