A new 2D metal coordination polymer (MCP), [Mn(pzdc)_0.5(L)]_n (1, pzdc = pyrazine-2,3-dicar- boxylic acid, HL = 3-(2-pyridyl)pyrazole), was synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, powder XRD, FT-IR, TG, fluorescence and elemental analysis techniques. Pale yellow crystals crystallize in orthorhombic system, space group Fdd2 with a = 11.2368(6), b = 38.280(2), c = 10.5682(6) Å, V = 4545.9(4) ų, C₁₁H₇MnN₄O₂, M_r = 282.15, D_c = 1.649 g/cm³, μ(MoKα) = 1.159 mm^-1, F(000) = 2272, Z = 16, the final R = 0.0613 and wR = 0.1773 for 2856 observed reflections (I > 2s(I)). It shows a two-dimensional network structure and is further assembled into a three-dimensional supramolecular framework via hydrogen bonds and abundant π-π interactions. In addition, we analyzed natural bond orbital (NBO) of 1 in using the PBE0/LANL2DZ method established in Gaussian 03 Program. There is obvious covalent interaction between the coordinated atoms and Mn(II) ions.