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Two novel six-coordinated zinc complexes, tetra-aqua(1,10-phenanthroline)zinc dinitrate monohydrate, [Zn(H2O)4(phen)](NO3)2·H2O (1) and aqua(2,2′-bipyridine)(imidazole)-nitratozinc nitrate, [ZnNO3(H2O)(bipy)(Him)]NO3 (2) were prepared. Compound 1 crystallizes in the monoclinic space group P21/c with a = 8.780(4), b = 13.609(4), c = 15.368(5) Å, β = 93.86(2)°C, V = 1832.1(12) Å3. In 1, a phenanthroline molecule chelates the zinc atom and four water molecules complete the octahedral geometry around the metal. Compound 2 crystallizes in the monoclinic space group P21/n with a = 7.250(1), b = 24.554(4), c = 10.258(2) Å, β = 107.880(10)°, V = 1737.9(5) Å3. In 2, a bipyridine molecule and a nitrate anion chelate the zinc atom. An imidazole molecule and a water molecule then complete the six-coordinated geometry around zinc. The intermolecular packing is controlled by hydrogen bonding, especially in 1 and by π stacking. The thermal stability of the compounds and the loss of water molecules and ligands was monitored by a thermogravimetric study.