FIELD: material engineering. SUBSTANCE: invention relates to the field of luminescent compounds with a heterocyclic 2,2':6',2"-terpyridine core, which can be applied in biology and medicine, as well as in research laboratories. A new compound, 5-Phenyl-5"-p-tolyl-2,2':6',2"- terpyridine 1, has been proposed, a “turn-on” chemosensor (probe) for Zn²⁺ ions. EFFECT: providing an effective luminescent chemosensor (probe) for the Zn²⁺ ion, for a qualitative assessment of the presence of zinc ions in food, cosmetics and human urine. 1 cl, 15 dwg, 3 tbl, 5 ex.