In this study, heterostructured g-Csub.3Nsub.4/Ag–TiOsub.2 nanocomposites were successfully fabricated using an easily accessible hydrothermal route. Various analytical tools were employed to investigate the surface morphology, crystal structure, specific surface area, and optical properties of as-synthesized samples. XRD and TEM characterization results provided evidence of the successful fabrication of the ternary g-Csub.3Nsub.4/Ag–TiOsub.2 heterostructured nanocomposite. The heterostructured g-Csub.3Nsub.4/Ag–TiOsub.2 nanocomposite exhibited the best degradation efficiency of 98.04% against rhodamine B (RhB) within 180 min under visible LED light irradiation. The g-Csub.3Nsub.4/Ag–TiOsub.2 nanocomposite exhibited an apparent reaction rate constant 13.16, 4.7, and 1.33 times higher than that of TiOsub.2, Ag–TiOsub.2, and g-Csub.3Nsub.4, respectively. The g-Csub.3Nsub.4/Ag–TiOsub.2 ternary composite demonstrated higher photocatalytic activity than pristine TiOsub.2 and binary Ag–TiOsub.2 photocatalysts for the degradation of RhB under visible LED light irradiation. The improved photocatalytic performance of the g-Csub.3Nsub.4/Ag–TiOsub.2 nanocomposite can be attributed to the formation of an excellent heterostructure between TiOsub.2 and g-Csub.3Nsub.4 as well as the incorporation of Ag nanoparticles, which promoted efficient charge carrier separation and transfer and suppressed the rate of recombination. Therefore, this study presents the development of heterostructured g-Csub.3Nsub.4/Ag–TiOsub.2 nanocomposites that exhibit excellent photocatalytic performance for the efficient degradation of harmful organic pollutants in wastewater, making them promising candidates for environmental remediation.