Used in bioconjugation processes to link biomolecules such as peptides, proteins, or antibodies with other functional molecules. The maleimide group selectively reacts with thiol groups (-SH) in cysteine residues, enabling site-specific modification. The PEG3 spacer improves solubility, reduces aggregation, and increases the stability of the conjugate in biological environments. The Boc-protected amine allows for further chemical modifications when needed, making it useful in drug development, targeted therapies, and diagnostic applications. Commonly employed in the synthesis of antibody-drug conjugates (ADCs) and PEGylation strategies.