Azo pyrazolones and their copper(II) complexes were characterized by elemental analyses, IR, 1H NMR, UV–Visible and magnetic measurements as well as thermal analysis and X-ray diffraction. The molar conductance measurements proved that all the complexes are nonelectrolytes. IR spectra showed that the ligands (HLn) acts as a monobasic bidentate ligand by coordinating via the nitrogen atom of the pyrazole ring (HNN) and oxygen atom of the deprotonated OH group moiety, thereby forming a square planar chelating ring with bidentate acetate group. Analytical data revealed that all the complexes exhibited 1:1 (metal-ligand) ratio. The Thermal decomposition of the complexes revealed the outer water molecules and acetate group as well as the end product is CuO. The thermodynamic parameters of the ligands (HLn) and their Cu(II) complexes are calculated using Coats–Redfern and Horowitz-Metzger methods. The optimized bond lengths, bond angles and the calculated quantum chemical parameters for the ligands (HLn) and their Cu(II) complexes (1–3) were investigated. The calf thymus DNA binding activity of the ligands (HLn) and their Cu(II) complexes were studied by absorption spectra and viscosity measurements. Molecular docking was used to predict the binding between the ligands and the receptor of 2a91-hormone of prostate cancer and 3hb5-oxidoreductase receptor of breast cancer.