• Cyclic voltammetry of various hydroxynicotinic acid (OHNA) ligands in dimethylsulfoxide. • Cyclic voltammetry of copper (II) complexes with various hydroxynicotinic acids in dimethylsulfoxide. • UV-Visible spectroscopy of various hydroxynicotinic acid (OHNA) ligands. • UV-Visible spectroscopy of copper (II) complexes with various hydroxynicotinic acids. • FT-IR spectroscopy of various hydroxynicotinic acids and their complexes. Herein reported the spectral and electrochemical properties of various hydroxynicotinic acids (OHNAs) viz; 2-, 3-, 4-, 5-, and 6-hydroxynicotinic acids and their copper(II) complexes were investigated in 1:2 (metal: ligand) molar ratio in dimethylsulfoxide by using cyclic voltammetry (CV). All cyclic voltammetric waves in OHNA-copper (II) complexes exhibits to OHNA-ligand based electrochemical reactions because of the similarities of the cyclic voltammograms between the OHNAs ligand and copper (II) complexes. The electrochemical behavior of copper(II) complexes with OHNAs ligand have shown that the reduction potential (Epc) shift toward less negative potential, while the oxidation peak potential (Epa) becomes more negative as compared to the used respective ligand clearly indicating that the reduction becomes easier on complexation. The FT-IR and electronic absorption spectroscopy of the hydroxynicotinic acids and their complexes have also been recorded in water/DMSO.