Boc-NH-PEG4-C2-Boc（Cat No.:I044638）is a symmetrical, bifunctional polyethylene glycol (PEG) linker featuring two Boc-protected amine groups at each end, separated by a four-unit PEG chain and a two-carbon alkyl spacer. The Boc (tert-butoxycarbonyl) groups protect the amines during synthetic steps and can be easily removed under mild acidic conditions to expose reactive primary amines. The PEG4 spacer enhances solubility, flexibility, and reduces nonspecific interactions. This reagent is ideal for stepwise synthesis, bioconjugation, and the construction of multifunctional molecules or polymer architectures in biomedical, pharmaceutical, and materials science applications.