Agnihotri R, Akhtar S, Singh A and Agnihotri N
4H-1-benzopyrans and their derivatives have been used widely as analytical reagents for the spectrophotometric determination of several transition metal ions. The present article reviews the importance of 4H-1-benzopyrans as analytical or complexing or chelating agent and fundamental conditions of several methods used for analytical determination of metal ions spectrophotometrically.