The solution studies the proton – ligand stability constant pK and metal ligand stability constants logk of binary (1:1) complexes of Cu(II), Co(II), Cd(II) and Ni(II)  with substituted thiocarbamido phenols have been studied at 0.1 M ionic strength in  70% ethanol-water mixture by Bjerrum method as adopted by Calvin and Wilson. It is observed that Cu(II), Co(II), Cd(II) and Ni(II) metal ions form 1:1 and 1:2 complexes with ligands (L1 & L3). The information acquired was used to estimate and compare the values of proton –ligand stability constant (pK) and metal-ligand stability constants (logk). The effects of substituents were studied from the evaluated information (pK and logk).