N-4-Hydroxyphenyl-N'-1,2,3-thiadiazol-5-ylurea-d4 is labelled N-4-Hydroxyphenyl-N'-1,2,3-thiadiazol-5-ylurea (H949385) which is a substrate of cytokinin O-glucosyltransferase with position specificity related to receptor recognition. It is a metabolite of Thidiazuron (T344275) which is a non-purine containing urea derivative with cytokinin activity.