Used as a fluorescent dye in biological imaging and staining applications. Its structure allows for strong absorption and emission of light, making it suitable for labeling biomolecules such as proteins and nucleic acids. Commonly employed in flow cytometry, fluorescence microscopy, and immunoassays due to its high photostability and compatibility with common detection instruments. The sulfonate group enhances water solubility, improving performance in aqueous biological environments. Also utilized in diagnostic kits and cellular tracking studies where precise, long-term visualization is required.