Used in bioconjugation processes to link molecules such as peptides, proteins, or dyes to other compounds. The NHS ester group reacts efficiently with primary amines, forming stable amide bonds, making it ideal for labeling biomolecules in assays, drug development, and diagnostic applications. The N3 (azide) group allows for click chemistry, particularly copper-catalyzed azide-alkyne cycloaddition, enabling selective and modular assembly of complex molecular structures. Commonly applied in proteomics, imaging, and targeted delivery systems where precise molecular attachment is required.