The thiosemicarbazide and hydrazide Cu(II) complexes, [Cu 3 L 2 1 (py) 4 Cl 2 ] (1), [Cu(HL 2 )py] (2) and [Cu(HL 3 )py] (3), (H 2 L 1 = 1-picolinoylthiosemicarbazide, H 3 L 2 = N 0 -(2-hydroxybenzylidene)-3-hydroxy-2-naphthohydrazide, H 3 L 3 = 2-hydroxy-N 0 -((2-hydroxy-naphthalen-1-yl)methylene)benzohydrazide) have been prepared and characterized through physicochemical and spectroscopic methods as well as X-ray crystallography. Complex 1 has a centrosymmetric structure with -N-N-bridged Cu 3 skeleton. Neighboring molecules are linked into a 3D supermolecular framework by p-p stacking interactions, N-HÁÁÁCl and C-HÁÁÁCl hydrogen bonds. Complexes 2 and 3 have similar planar structures but different dimers formed by concomitant CuÁÁÁN and CuÁÁÁO interactions, respectively. Solvent accessible voids with a volume of 391 Å 3 are included in the structure of complex 2, indicating that this complex is a potential host candidate. Thermogravimetric analysis shows that the three complexes are stable up to 100°C.