An interesting T4（2）5（2） water tape formed by fused cyclic water pentamers and tetramer was self-assembled in a new inorganic host [Ni（L）（phen）2]·5H2O （L = L-cysteic acid） and characterized by X-ray diffraction. Each [Ni（L）（phen）2] molecule crystallizes with five water molecules with a molecular formula of [Ni（L）（phen）2]·5H2O. The T4（2）5（2） water tape and [Ni（L）（phen）2] molecules assemble into a network of water tapes sandwiched between [Ni（L）- （phen）2] tapes. The network is stabilized by π-π stacking between [Ni（L）（phen）2] molecules and three types of hydrogen-bonding interactions between [Ni（L）（phen）2] molecules, water molecules, and water and [Ni（L）（phen）2] molecules.
