8-Hydroxy-2-quinolinecarboxylic acid (8HQC) is a tridentate chelating agent. It reacts with 2-aminophenol to form a benzoxazole derivative, which can undergo fluorescence quenching in water, making it a viable candidate for developing a probe for detecting water in aprotic organic solvents. The analysis of mid-IR and Raman spectra of 8HQC shows the presence of seven tautomers. Application： 8-Hydroxy-2-quinolinecarboxylic acid may be used in the preparation of bis (8-hydroxyquinoline-2-carboxylato-Κ3N,O,O′) cobalt (II) trihydrate