We report a successful synthesis of the composite of quadruple perovskite, CaCu3Ti4O12 (CCTO) with graphitic carbon nitride (g-C3N4; CN) that is shown to be highly active for methylene blue (MB) degradation in aqueous medium in the presence of H2O2 activator under domestic LED light irradiation. Comparison of activity behavior of the composite with the respective pristine materials, CCTO and CN, shows the onset of a synergistic effect beyond 5 wt% loading of CN. Notably, the 10 wt% CN loaded CCTO (CN1OCCTO) shows excellent enhancement in photocatalytic activity (achieving MB removal similar to 96%). The pristine CCTO was prepared via a citrate combustion route, while g-C3N4 was prepared by a thermal heat treatment method. The composite materials have been synthesized by low temperature (similar to 150 degrees C) thermal treatment of an intimate physical mixture of the components in desired composition (w/w). The materials are characterized by using powder X-ray diffraction (P-XRD), Fourier transform infrared (FTIR) spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence (PL) spectroscopy, transient photoresponse, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanism of photodegradation is studied by performing the oxidation in presence of various types of scavengers, which have revealed the involvement of multiple types of radicals in the degradation process with first order kinetics. The scavenger-fluorescence study have strengthen the findings on mechanism of degradation. The enhanced activity of the composite material is ascribed to the easy availability of the charge carriers in the composite as evidenced from the band energy diagram suggested on the basis of cyclic voltammetry measurement. The recycling test clearly indicates the uninterrupted performance of the material without losing its activity.