A μ-dichloro-bridged tetranuclear Cu(II) bis(salamo)-type complex [Cu4(HL)2Cl2(μ2-Cl)2]·6MeOH was synthesized by reaction of the ligand H3L and CuCl2·2H2O in ethanol–CHCl3 solution, and characterized by elemental analysis, IR and UV-Vis spectroscopy, as well as single-crystal X-ray crystallography data. The DFT calculation for the ligand H3L and its Cu(II) complex revealed there is a change in the ICT effect due to the coordination of the Cu(II) atoms, which explains well the fluorescence quenching. The IRI analysis indicated that the Cu(II) atoms are strongly bound to the ligand H3L. The Hirshfeld surface analysis illustrated that H–H interactions are the main interactions in the Cu(II) complex. Finally, the fluorescence properties of the ligand H3L and its Cu(II) complex were studied in DMF solution and solid state. [ABSTRACT FROM AUTHOR]