The ligand of 6-(4-benzenesulfonic acid azo)-3-aminophenol (HL) is prepared and characterized by elemental analyses, IR, ¹H NMR spectra, mass spectra and X-ray diffraction analysis. The proton–ligand dissociation constants of HL ligand and its metal stability constants with Mn(II), Co(II), Ni(II) and Cu(II) ions have been determined using potentiometric studies as described by Irving and Rossotti. The optimized structure and the calculated quantum chemical parameters of HL ligand were studied. The potentiometric studies were carried out in 0.1 M KCl and 20% (by volume) DMF–water mixture. The effect of different temperatures was studied and the thermodynamic functions (ΔG, ΔH and ΔS) were calculated. The dissociation process is non-spontaneous, endothermic and entropically unfavorable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropically favorable. Molecular docking was used to predict the binding between azo dye ligand and the receptor of prostate cancer mutant 2q7k-hormone and the receptor of breast cancer mutant 3hb5-oxidoreductase.