Azido-PEG3-maleimide is widely used in bioconjugation and chemical biology for linking biomolecules. Its azide group allows for click chemistry reactions, such as the copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling efficient and selective attachment to alkyne-functionalized molecules. The maleimide group reacts specifically with thiol groups, making it ideal for conjugating peptides, proteins, or antibodies containing cysteine residues. This compound is particularly valuable in drug delivery systems, where it facilitates the targeted attachment of therapeutic agents to carriers or antibodies. It is also employed in the development of biosensors, where it helps immobilize biomolecules on surfaces while maintaining their activity. Additionally, its PEG spacer enhances solubility and reduces steric hindrance, improving the efficiency of conjugation processes.