Enzyme-mediated activation of radical sources (EMARS) is a proximity labeling method that identifies neighboring molecules within a range of 300 nm from any target molecule. Possible applications in glycoscience include (1) finding molecules localized in specific glycolipid microdomains, (2) finding molecules co-localized with specific GPI-anchored proteins, (3) finding neighboring molecules of glycoproteins that lectins bind to, and (4) identifying receptors that use specific glycolipids as ligands.