Three new complexes [Cd(H2biim)(2,2'-bipy)(NO3)2] (1), [Cu(H2biim)(2,2'-bipy)(H2O)](NO3)2 (2) and [Zn(H2biim)(2,2'-bipy)(H2O)](NO3)2 (3) (H2biim＝2,2'-biimidazole; 2,2'-bipy＝2,2'-bipyridine) have been synthesized and characterized by X-ray single crystal diffraction. In 1, the Cd(II) atom is coordinated by two nitrogen atoms from one H2biim ligand, two nitrogen atoms from one 2,2'-bipy ligand and two oxygen atoms from two nitrate anions. In 2 and 3, Cu(II) and Zn(II) atoms are coordinated by two nitrogen atoms from one H2biim ligand, two nitrogen atoms from one 2,2'-bipy ligand and one oxygen atom from one H2O ligand. By multiple robust hydrogen bonds R21(7), R21(4) and R44(18) formed by NH groups of 2,2'-biimidazole, oxygen atoms of nitrate anions and water molecules, complexes 1～3 extend one-dimensional zigzag chains.

Key words: 2,2-biimidazole, 2,2-bipy, cadmium(II) complex, copper(II) complex, zinc(II) complex, crystal structure