The metal ions Cu(II), Cd(II), Co(II) and Ni(II) interacted with ligand 4-phenylthiocarba- midophenol have been studied at 0.1 M ionic strength in 70 % ethanol-water mixture by Bjerrum method as adopted by Calvin and Wilson. It was observed that Cu(II), Cd(II) and Cr(III) metal ions form 1:1 complexes with ligand 4 phenylthiocarbamidophenol. The values of proton-ligand stability constant (pK) and metal-ligand stability constants (log k) were estimate and compared from resultant data. The effects of substituent were studied from estimated data (pK & log k).