Bismuth(III) chloride oxide (BiOCl) is primarily used as a pearlescent pigment in the cosmetics industry, imparting a shimmering, iridescent effect to products like lipsticks, eyeshadows, nail polishes, and other personal care items. It serves as a precursor in the synthesis of bismuth-containing pharmaceuticals, such as those for treating peptic ulcers and as radiopaque agents in medical imaging. In materials science, it is applied in the development of bismuth-based nanomaterials, photocatalysts, and semiconductors due to its unique optical and electronic properties. Compared to other heavy metal compounds, it exhibits low toxicity, making it suitable for safer, environmentally friendly chemical processes.