Boc-NH-PEG-COOH is widely used in bioconjugation and pharmaceutical development due to its dual functional groups. The carboxylic acid (COOH) end allows for easy coupling to amines, forming stable amide bonds, commonly used to link peptides, proteins, or drugs. The Boc-protected amine (Boc-NH-) provides a handle for further modification after deprotection, enabling controlled stepwise synthesis.

This compound is especially valuable in drug delivery systems, where PEGylation improves solubility, reduces immunogenicity, and extends the circulation time of therapeutic molecules. It is also used in the preparation of PEG-based linkers in antibody-drug conjugates (ADCs) and in surface modification of nanoparticles and medical devices.

Additionally, Boc-NH-PEG-COOH serves as a building block in solid-phase peptide synthesis and in the creation of functionalized polymers for hydrogels and biosensors. Its PEG spacer offers flexibility and reduces steric hindrance, enhancing binding efficiency in bioactive constructs.