A simple fluorescent sensor of zinc-terpyridine complex of the terpyridine ligand 4'-(3,4,5-trimethoxyphenyl)-2,2' : 6',2''-terpyridine was prepared and utilized for selective sensing of pyrophosphate anion (PPi) in aqueous medium at physiological pH. The sensor complex showed an excellent selectivity of PPi over various other anions such as Cl À , F À , Br À , I À , CO 3 2À , HCO 3 À , NO 3 À , OH À , HPO 4 2À , SO 4 2À , SO 3 2À , S 2 O 3 2À in water. UV-Visible and fluorescence spectroscopic method have been used to perform the detection study. The sensor complex showed~50 fold enhancement of fluorescence intensity upon addition of PPi and excellent sensitivity with lowest limit of detection (LOD) for the detection of PPi anion was found to be~300 nM.