An α-D-N-acetylgalactosamine (GalNAcα) ligand equipped with a methyl ester-protected carboxylic acid through a short butyl spacer. The methyl ester serves as a stable, protected form of the carboxylic acid that can be hydrolyzed under mild basic conditions (e.g., LiOH, NaOH) to unmask the free acid for downstream activation to NHS, sulfo-NHS, or pentafluorophenyl (PFP) esters and subsequent coupling to amine-functionalized platforms or lysine residues on proteins and peptides. This compound enables the construction of hepatocyte-targeted therapeutics and research tools that exploit the asialoglycoprotein receptor (ASGPR), which is highly expressed on liver hepatocytes and binds GalNAc-containing ligands with high affinity. The terminal GalNAcα residue is also a substrate for glycosyltransferases, including galactosyltransferases and sialyltransferases, enabling enzymatic chain extension.