A new two-dimensional （2D） manganese（II） coordination polymer {[Mn（bidc）（H2O）2]· 2H2O}n （H2bidc = benzimidazole-5,6-dicarboxylic acid） was synthesized, and characterized by X-ray crystallography and other measurements. The complex crystallizes in the orthorhombic system, space group Pbca with a = 7.0218（7）, b = 17.9701（18）, c = 19.0697（19）, V = 2406.3（4）3, Z = 8, Dc = 1.823 g/cm3, Mr = 330.14, F（000） = 1344, μ（MoKα） = 1.140 mm-1, S = 1.055, R = 0.0305 and wR = 0.1012 for 2130 observed reflections （I 2σ（I））. The title complex consists of a novel 2D network with a topology of short symbol （4.82）（4.82）.
