Azido-PEG24-NHS ester is widely used in bioconjugation and chemical biology for attaching biomolecules to surfaces or other molecules. Its azide group enables click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), which is highly efficient and selective. This makes it valuable for labeling proteins, peptides, and other biomolecules without disrupting their function. The NHS ester group allows for covalent bonding with primary amines, facilitating the modification of amino acids, antibodies, or other amine-containing compounds. Additionally, its PEG spacer enhances solubility and reduces steric hindrance, improving reaction efficiency. This compound is instrumental in drug delivery systems, surface functionalization, and the development of diagnostic tools and biomaterials.