N-(Azido-PEG2)-N-Boc-PEG4-acid is widely used in bioconjugation and chemical biology research. Its azide group enables click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), making it valuable for labeling biomolecules such as proteins, peptides, and nucleic acids. The Boc (tert-butoxycarbonyl) protecting group allows for selective deprotection, facilitating controlled synthesis of complex molecules. The PEG (polyethylene glycol) spacers enhance solubility and reduce steric hindrance, improving reaction efficiency. This compound is instrumental in drug delivery systems, where it helps create targeted and stable conjugates. Additionally, it is utilized in the development of biosensors and diagnostic tools, enabling precise attachment of functional groups to substrates. Its versatility also supports material science applications, such as surface modification and polymer functionalization.