An ion-pair compound, [HL]2[Ni(CN)4]4H2O 1 has been obtained as an unexpected product when we attempt to prepare a heterometallic cyano-bridged complex by the reaction of GdCl3nH2O, K2Ni(CN)4 and L (L=4-(2-hydroxyphenyl)-1,5,9-triazacyclododecan-2-one) in aqueous solution, and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a = 12.380(1), b = 9.9637(8), c = 17.087(1) ? ?= 105.947(2)? V = 2026.6(3) ?, Rint = 0.0509, Z = 2, Dc = 1.297 g/cm3, C34H56O8N10Ni, Mr = 791.60, F(000) = 844, m(MoKa) = 0.538 mm1, S = 1.030, the final R = 0.0644 and wR = 0.1299 for 2023 observed reflections with I ≥ 2(I). The title compound 1 contains one anion of [Ni(CN)4]2, two cations of [HL]+ and four packing water molecules, which are held together by the NH···O and OH···O hydrogen bonds to form a three- dimensional framework. Anion-pair compound, [HL] 2 [Ni (CN) 4] 4H2O 1 has been obtained as an unexpected product when we attempt to prepare a heterometallic cyano-bridged complex by the reaction of GdCl3nH2O, K2Ni (CN) 4 and L (L = 4- (2-hydroxyphenyl) -1,5,9-triazacyclododecan-2-one) in aqueous solution, and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21 / n with a = 12.380 (1), b = 9.9637 (8), c = 17.087 (1) = 105.947 (2), V = 2026.6 (3), Rint = 0.0509, Z = 2 and Dc = 1.297 g / cm3. The final R = 0.0644 and wR = 0.1299 for 2023 observed reflections with I ≥ 2 (I). The title compound 1 is C34H56O8N10Ni with Mr = 791.60, F (000) = 844, m (MoKa) = 0.538 mm1, S = 1.030, contains one anion of [Ni (CN) 4] 2, two cations of [HL] + and four packing water molecules, which are held together by the NH ··· O and OH ··· hydrogen bonds to form a three- dimensional framework.