An α-L-rhamnose ligand equipped with a maleimide through a hydrophilic PEG12 spacer. The maleimide reacts selectively with free thiols, such as cysteine residues, to form stable thioether conjugates. This compound provides an α-L-rhamnose building block for glycoconjugate synthesis and the construction of probes that exploit naturally occurring anti-rhamnose antibodies, with applications in antibody-recruiting molecule and immunotherapy research.