A triantennary N-acetylgalactosamine (Tri-GalNAcβ) ligand presenting three β-GalNAc residues on a tris-based branched scaffold, equipped with a terminal carboxylic acid through a discrete, monodisperse pentaethylene glycol (PEG5) spacer. The carboxylic acid can be activated to NHS, sulfo-NHS, or pentafluorophenyl (PFP) esters and reacted with amine-functionalized payloads, antibodies, peptides, or lysine residues on proteins to form stable amide bonds. This compound enables the construction of hepatocyte-targeted therapeutics and research tools that exploit the asialoglycoprotein receptor (ASGPR; Ashwell-Morell receptor), which is highly expressed on liver hepatocytes and binds GalNAc-containing ligands with high affinity. The trivalent presentation of GalNAcβ residues engages multiple carbohydrate-recognition domains of ASGPR simultaneously, producing high-avidity binding that substantially exceeds the affinity of monovalent GalNAc ligands and closely mimics the geometry of clinically validated Tri-GalNAc targeting moieties used in approved GalNAc-siRNA therapeutics. In particular, Tris-GalNAc-PEG5-COOH has a central role in lysosomal-targeting chimera (LYTAC) technology, where the Tri-GalNAc moiety is attached to a target-protein ligand to direct extracellular and membrane proteins to the lysosome for degradation via ASGPR-mediated endocytosis in hepatocytes.