Quantitative determination of a number of ions like Cu, Ag, Zn, Fe, Ni, Co, Cd etc. has been done by using 1.2.3-benztiazole as precipitating agent under different experimental conditions. This is just one such reagent out of many known ligands. Specific reagents like dimethylglyoxime are used to isolate red Ni(I1) complex and cupferron is used for the estimation of Fe, Ti etc..