A new dinuclear copper (II) complex of 2,5-furandicarboxyclic acid with 4(5)-methylimidazole, [Cu (FDCA)((4(5)MeI)(2)](2)center dot 2H(2)O, was synthesized, and its structure characterized by XRD, FT-IR and UV-Vis spectroscopic techniques. The alpha-glucosidase inhibition and cytotoxicity study of the synthesized Cu (II) complex were determined by IC50 values. The optimized geometry and vibrational harmonic frequencies for the Cu (II) complex were obtained by using Density Functional Theory (DFT) of HSEh1PBE/6-311++G(d,p)/LanL2DZ level. TD-DFT/HSEh1PBE/6-311++G(d,p)/LanL2DZ level with CPCM model was applied to examine the electronic spectral properties and major contributions were determined via Swizard program. To investigate linear and nonlinear optical behavior of the synthesized Cu (II) complex, the alpha, Delta alpha and chi((1))/beta, gamma and chi((3)) parameters called linear/nonlinear optical parameters in gas phase and ethanol solvent were computed at the same level and basis set. Furthermore, molecular electrostatic potential (MEP) surface was determined by using the same level. The docking study of the Cu (II) complex to the binding site of the target protein (the template structure S. cerevisiae isomaltase) is fulfilled. Natural bond orbital (NBO) analysis was used to investigate the hyperconjugative interactions, inter- and intra-molecular bonding and to determine coordination around Cu (II) ion. Finally, present work is the first remarkable scientific report of mixed-ligand (H(2)FDCA and 4(5)MeI) Cu (II) complex as novel drug candidate for DM II. It is also determined that microscopic third-NLO parameters for the Cu (II) complex is remarkable.