Used in bioconjugation and chemical biology, Propargyl-PEG4-5-nitrophenyl carbonate serves as a linker for attaching functional groups to biomolecules. Its propargyl group enables click chemistry reactions, while the PEG4 spacer enhances solubility and reduces steric hindrance. The 5-nitrophenyl carbonate moiety allows for efficient coupling with amines, making it valuable in synthesizing drug conjugates, modifying proteins, and creating targeted delivery systems. It is particularly useful in developing antibody-drug conjugates (ADCs) and other therapeutic platforms.