NH2-C2-amido-C2-Boc is a specialized linker reagent used in peptide synthesis, featuring a free primary amine (NH2) at one end and a Boc (tert-butoxycarbonyl)-protected amine at the other, connected via an amide linkage with ethylene spacers (H2N-CH2-CH2-NH-CO-CH2-CH2-NH-Boc). This structure allows it to serve as a bifunctional spacer in solid-phase peptide synthesis (SPPS), where the free amine can be selectively coupled to a growing peptide chain, while the Boc group protects the distal amine to prevent unwanted reactions. The Boc protection is stable under basic conditions but readily removed under acidic conditions (e.g., with TFA), enabling stepwise deprotection and attachment of additional residues or functional groups. It is particularly useful for introducing flexible ethylene-based linkers in peptide conjugates, pharmaceuticals, and bioactive molecules, facilitating precise control over molecular architecture and improving solubility or targeting properties.