The stability constants of complexes formed by Thallium (I) with Serine and Leucine have been investigated in aqueous medium, the complex with metal Serine as 1:1, 1:2 and complexes of the Tl(I) with Leucine as 1:1, 1:2 have been reported. The values of formation constant of Serine are log β1 = 2.1760, log β2 = 3.85325 at 308K and log β1 = 1.9030, log β2 = 3.6739 at 318K and complexes of Tl(I) ...