Semiconductor photocatalysts that are robust and galvanized by visible light have been increasingly sought after, with lead bismuth oxyhalide (PbBiO2X)-which constitutes a perovskite-like semiconductor-receiving vast attention recently. We noted, after a relevant literature survey, that tetragonal lead bismuth oxyiodide/bismuth oxyiodide/graphitic carbon nitride (t-PbBiO(2)l/Bi(5)O(7)l/g-C3N4)-supported crystal violet (CV) dye photocatalytic degradation under irradiation with visible light has yet to be reported. The current study provides the report of t-PbBiO(2)l/Bi(5)O(7)l/g-C3N4 composite isolation and characterization realized through field-emission scanning electron microscopy-energy-dispersive spectroscopy, X-ray diffraction, high-resolution X-ray photoelectron spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, Brunauer-Emmett-Teller analysis, Fourier-transform infrared spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy. Catalytic performance observation revealed that using t-PbBiO(2)l/Bi(5)O(7)l/g-C3N4 resulted in an optimal reaction rate constant of 0.3518 h(-1), a derivation exceeding the derivations for the photocatalysts t-PbBiO(2)l, Bi(5)O(7)l, g-C3N4, and t-PbBiO(2)l/Bi(5)O(7)l by 15, 6.6, 13.1, and 1.4 times, respectively. As demonstrated by the quenching effects associated with diverse scavengers, the electron paramagnetic resonance results revealed reactive O-2(-) to have a major role in the CV dye degradation. The paper proposes and also describes possible photodegradation mechanisms. The method that was realized in this study is valuable for PbBiO(2)l/Bi(5)O(7)l/g-C3N4 synthesis and CV dye photocatalytic degradation for future applications in environmental pollution regulation. (C) 2018 Elsevier Inc. All rights reserved.