Widely used in bioconjugation, this compound acts as a fluorescent labeling reagent for biomolecules such as proteins, peptides, and antibodies. Its NHS ester group reacts efficiently with primary amines under mild conditions, forming stable amide bonds, making it ideal for preparing fluorescent conjugates. The benzoxadiazole core provides strong fluorescence with high quantum yield, particularly useful in detection and imaging applications. It is commonly applied in fluorescence microscopy, flow cytometry, and immunoassays due to its bright emission and good photostability. The sulfonamide group enhances water solubility, allowing labeling in aqueous buffers with minimal organic solvent. Its long alkyl spacer improves flexibility and reduces steric hindrance, leading to better labeling efficiency and preserved biological activity of the target molecule.