Used as a fluorescent tracer in water systems to monitor flow and detect leaks due to its bright color and visibility under UV light. Commonly applied in environmental studies for tracking water movement in rivers, groundwater, and drainage systems. Also used in histology as a stain for microscopic tissue examination, providing contrast to cellular structures. In some medical applications, it acts as a photosensitizer in photodynamic therapy for treating certain skin conditions. Its water solubility makes it suitable for biological and aqueous-based staining procedures.