Used as a key intermediate in the synthesis of pharmaceuticals and bioconjugation reagents, particularly in the development of antibody-drug conjugates (ADCs) and targeted therapeutics. Its amine and ester functionalities allow for selective coupling reactions, enabling the attachment of drugs to targeting moieties such as antibodies or peptides. The hydrophilic ethylene glycol linker enhances solubility and stability in aqueous environments, improving pharmacokinetic properties of the final conjugate. Also employed in the preparation of PEGylated compounds to increase drug circulation time and reduce immunogenicity. Commonly utilized in research settings for modifying biomolecules and constructing functionalized polymers for drug delivery systems.