Crystal structure determination of the two substances Cu3(NTA)2(4,4‘-bpy)2(H2O)2]·9H2O (1) and [{Cu(4,4‘-bpy)(H2O)4}{Cu2(NTA)2(4,4‘-bpy)}]·7H2O (2) reveals that 1 has layer structure with cross-linking rhombic channels generated from helical chains. 2 contains rhombic channels generated from both covalent bonds and hydrogen bonds between the cations and dimeric anions.