The title compound, CHCuFNOS ( 1), was synthesized by the reaction of Cu( tta) and L, ( L = ( E)-2-(4-(1 H-1,2,4-triazol-1-yl)benzylidene)-3,4-dihydronaphthalen-1(2 H)-one) in the dichloromethane solution. It crystallizes in the monoclinic, space group P2/ c with a = 33.8388(5), b = 9.3874(2), c = 21.8194(4) Å, β = 95.522(2), V = 6898.9(2) Å, Z = 8, D = 1.554 Mg/m, F(000) = 3272, µ = 0.834 mm, R = 0.0639, wR = 0.1637. The copper(II) ion of 1 is in a distorted square-pyramidal environment with four O atoms of the two tta ligands and one N atom of triazole ligand L. Single-crystal X-ray diffraction data revealed that the hydrogen bonds, weak C-H···π and π···π interactions in the crystals link the coordination units to form 3D supramolecular structures. [ABSTRACT FROM AUTHOR]