Industrialization and Urbanization has lead to the use of heavy metal ions extensively in many areas of science. Industries effluents contain heavy metal ions like Mercury, Lead, Cadmium which enter into the food chain, and starts accumulating in human body. Mercury is non-biodegradable, it malfunctions metabolic activities in the body which may lead to death. Out of all, expensive spectroscopic techniques like ICP-MS. AAS etc., Spectrophotometric method is found to be simple, cost effective method but with moderate sensitivity. Dithizone is found to be a standard and extensively used chromogenic reagent in estimating Mercury ions. In this work, p-methoxy aniline and p-nitroaniline were diazotized and reduced to obtain respective phenyl hydrazines. A gummy, polymer like substance was formed instead of p-nitrophenyl hydrazine. Hence, p-methoxy phenyl hydrazine and 3,4,5-trimethoxyphenyl isothiocyanate were coupled followed by oxidation with N-BromoSuccinimide to obtain compound which was confirmed using 1H NMR. Estimation of divalent mercury was done using colorimeter and UV-Vis spectrophotometer.