Used primarily as a photochromic dye, this compound changes color when exposed to ultraviolet light, making it ideal for light-sensitive applications. It is commonly incorporated into photochromic lenses, where it enables automatic darkening in sunlight. Also used in specialty inks for security printing, authentication labels, and smart packaging that responds to UV exposure. Its reversible color change supports applications in sensors and optical switches. Due to strong visible color shift and fatigue resistance, it is favored in research and development of responsive materials and coatings.