Used primarily as a photochromic compound in optical materials. It changes color reversibly when exposed to UV light, making it suitable for photochromic lenses in eyeglasses that darken in sunlight. Also applied in smart windows, inks, and coatings where light-responsive behavior is needed. Its nitro group enhances the photochromic response speed and fatigue resistance, improving performance in repeated switching cycles. Employed in research for optical switches and sensors due to its rapid and stable color transition.