Two dysprosium(Ⅲ) complexes derived from 2,2’-bipyridine-6,6’-dicarboxylic acid(H_2bpdc),[Dy(bpdc)(Hbpdc)]-3H_2O(1) and[Dy_2(bpdc)_3(H_2O)_3]·2.125H_2O(2),were isolated from the same hydrothermal reaction container as different phases.Compound1 is a mononuclear complex with a DyN_4O_4 coordination polyhedron;whereas compound 2 is a dinuclear complex with two types of eight coordinated dy sprosium(Ⅲ) ions,showing DyN_4O_4 and DyN_2O_6 coordination polyhedra,respectively.Remarkably,a new type of(H_2O)_6 supramolecular aggregate exists in the crystal structure of 2.Magnetic investigations revealed that 1 is a field-induced single-ion magnet with an effective energy barrier of 45.6 K,exhibiting two-step magnetic relaxation;while an intramolecular ferromagnetic interaction exists in 2,which is a field-induced single-molecule magnet,displaying two-step magnetic relaxation too,with effective energy barriers of 53.4 and 92.1 K,respectively. Two dysprosium (Ⅲ) complexes derived from 2,2’-bipyridine-6,6’-dicarboxylic acid (H_2bpdc), [Dy (bpdc) (Hbpdc)] - 3H_2O and Dy_2 (bpdc) _3] · 2.125H_2O (2), were isolated from the same hydrothermal reaction container as different phases. Compound 1 is a mononuclear complex with a DyN_4O_4 coordination polyhedron; ions, showing DyN_4O_4 and DyN_2O_6 coordination polyhedra, respectively. Remarkably, a new type of (H_2O) _6 supramolecular aggregate exists in the crystal structure of 2. Magnetic investigations revealed that 1 is a field-induced single-ion magnet with an effective energy barrier of 45.6 K, exhibiting two-step magnetic relaxation; while an intramolecular ferromagnetic interaction exists in 2, which is a field-induced single-molecule magnet, displaying two-step magnetic relaxation too, with effective energy barriers of 53.4 and 92.1 K, respectively .