The adsorptive photocatalytic degradation of indigo carmine dye in aqueous solution onto copper hydroxychloride-cuprous chloride has been examined. The sample was characterized using X-ray powder diffraction, infrared spectrum, UV-visible spectrum and scanning electron microscopy. Different concentrations of indigo carmine dye solutions with variation in the adsorbent dose of copper hydroxychloride-cuprous chloride mixture were used in the adsorptive photocatalytic degradation studies. Various adsorption isotherm models were used to assess the mechanism of photocatalytic degradation process of indigo carmine using copper hydroxychloride-cuprous chloride mixture.