This compound is widely used in bioconjugation and peptide synthesis due to its bifunctional nature. The Boc group serves as a protective group for amines, allowing selective reactions at other sites. The PEG4 spacer enhances solubility and reduces steric hindrance, making it ideal for linking molecules in drug delivery systems. The terminal carboxylic acid group enables covalent attachment to amines or other functional groups, facilitating the creation of stable conjugates. It is particularly valuable in the development of antibody-drug conjugates (ADCs), where it helps connect cytotoxic drugs to antibodies. Additionally, it is employed in the synthesis of peptide-based therapeutics and diagnostics, improving bioavailability and pharmacokinetics. Its versatility also extends to materials science, where it is used to modify surfaces or create functionalized polymers.