Thiosemicarbazones and their metal complexes have became the subject of intensive study due to their wide range of biological activity, analytical applications and interesting chemical and structural properties [1, 2]. Usually, thiosemicarbazones act as chelating ligands through the phenolate oxygen, azomethine nitrogen and sulphur atoms to form mononuclear complexes. In this work we report a polynuclear copper(II) - thiosemicarbazone compound {[Cu(HL1)(DMSO)] 0.5DMSO}n (1), where the N(2) nitrogen coordinates to a neighbour site, forming the 1D pattern (fig. 1).figureFig. 1. A sequence of the 1D structure of the compound 1figureFig. 2 Magnetic susceptibility as T vs. T curve. (circles=experimental, line=fitted)The single X ray diffraction analysis shows a monoclinic crystal with the P21/c space group and a = 9.67(2) Å, b =19.27(3) Å, c= 21.04(3) Å and = 95.25(11) o cell parameters. The Cu(II) is pyramidally coordinated, with the apical position occupied by the solvent. The equatorial subsystem is almost planar, made of the {OSN2} set of donors. The chain is developed along the N-Cu-N average trans axis, with very little asymmetry in Cu-N bond lengths (2.081 Å and 2.010 Å) and in the Cu…Cu long range distances (4.937 Å and 4.939 Å). Interpreting the chain as effectively homogenous, the magnetic susceptibility, fitted with Fisher’s formula, yields the g=2.19 gyromagnetic factor and the J=-130.2 cm-1 rather strong antiferromagnetic coupling (fig. 2). At low temperatures, a feature assignable to inter-chain interactions is visible.