A novel nickel( = 2 \* ROMAN II) complex [Ni(H₂tpda)(NCS)₂(CH₃OH)] was synthesized by using tripyridyl- diamine as ligand and Ni(NCS)₂ as starting materials, and characterized by a variety of techniques including single-crystal X-ray diffraction, IR spectroscopy and TG-DSC. The single-crystal structure reveals that the complex exhibits as a neutral molecule and that the central atom Ni(II) is octahedrally coordinated by an H₂tpda, two NCS^- ions and a ligand molecule CH₃OH. The 3D supramolecular network is formed through hydrogen bonds and π-π interactions. The complex can catalyze the addition reaction of carbon dioxide and propylene oxide.