A CuO-ZnO@graphitic carbon nitride (Cu/Zn/g) triplex heterojunction nanocomposite was prepared through a multistep ultrasound-assisted hydrothermal procedure. XRD, SEM, EIS, EDX, BET, FT-IR, EDS, UV-Vis, TEM, PL, and transient photocurrent techniques were employed for catalyst characterization. The XRD profiles demonstrated the formation of the ZnO wurtzite phase and CuO monoclinic phase in the samples. It was revealed by the SEM and TEM images that the Cu/Zn/g catalyst is composed of g-C3N4 nanosheets decorated with ZnO nanorods and CuO nanospheres. According to the results obtained from the ultrasound-assisted desulfurization experiments, almost complete sulfur removal was achieved using Cu/Zn/g at a photocatalyst dose of 0.2 g/L, initial dibenzothiophene (DBT) concentration of 250 ppm, and H2O2 loading of 250 ppm at 298 K within 60 min of treatment in the presence of ultrasonic waves (80 W/m(2)) and light irradiation (150 W). Upon g-C3N4 incorporation, considerable enhancement in desulfurization efficiency was achieved due to the significantly higher surface area and lower recombination rate of electron-hole pairs. At optimal experimental conditions, a 99.1% desulfurization rate was achieved using Cu/Zn/g with a g-C3N4 concentration of 10 wt %, compared to the pristine CuO-ZnO catalyst (76.2%). Moreover, the as-synthesized photocatalyst showed excellent stability after five cycles. Kinetic studies also confirmed that the desulfurization procedure could be fitted to a pseudo-firstorder kinetic model. Finally, the product of DBT oxidation was identified by the gas chromatography-mass spectrometry analysis. It was revealed on the basis of the photoelectrochemical and trapping experiments that the photoinduced holes and center dot OH radicals are responsible for desulfurization and the charge carrier migration pattern is dictated by the dual Z-scheme approach, resulting in the enhanced redox potential of the as-synthesized catalyst and therefore outstanding photocatalytic performance.