2,8-Quinolinediol is a quinolone derivative. It has been reported as metabolite of 8-hydroxyquinoline-N-oxide in rabbits. Synthesis of 2,8-quinolinediol has been reported. It is reported as one of the six possible forms of 8-hydroxycarbostyril. It has been detected as new UV-absorbing compound (UAC) in cow milk and its structure was elucidated using HRMS and by 1H, 13C and 1H ×13C NMR. It is also known as 8-hydroxycarbostyril or 8-hydroxyquinolin-2(1H)-one. 8-hydroxyquinolin-2(1H)-one has been reported as the tautomeric form of 2,8-quinolinediol. 2,8-Quinolinediol (2,8-Dihydroxyquinoline) has been identified as one of the metabolite of quinolone formed in the culture medium of gram-negative bacteria, Pseudomonas stutzeri.