Two copper(II) complexes, [Cu(im) 6 ]Cl 2 •4H 2 O (1), and [Cu(im) 6 ]Cl 2 •2H 2 O (2) (im = imidazole), have been synthesised. In compound 1, [Cu(im) 6 ] 2+ cations and Clcounter anions alternately array in an ABAB fashion via N-H…Cl hydrogen bonding. There are two kinds of hydrogen bonds, inter-and intramolecular hydrogen bonding interactions, which form 2-D sheets. However, an interesting polymeric network is formed from the weak intermolecular interactions in compound 2.