Treatment of LZrCl 2 (L=N,N ' -ethylenebis(3,5-di-tert-butylsalicylideneiminato) (1), N,N ' -o-phenylenebis(3,5-di-tert-butylsalicylideneiminato) (2)), which is an effective catalyst precursor for ethylene oligomerization, with 1.5 equiv of water in toluene afforded H 2 O-coordinating salen-type zirconium complexes [LZrCl 2 (H 2 O)]. The effects of the content of H 2 O and the temperature on the equilibrium of association and disassociation of H 2 O molecule in [LZrCl 2 (H 2 O) n ] (n=0, 1) were studied in solution (CDCl 3 ) by 1 H NMR spectroscopy. The crystal and molecular structure of [1(H 2 O)] was determined by X-ray diffraction analysis, which revealed that a herringbone supramolecular assembly was constructed in the crystalline state of [1(H 2 O)], stacked by the intermolecular hydrogen bonds between the OH group of the coordinating H 2 O and one of the chloride ligands.