A new dinuclear manganese complex [Mn_2(L)_2(2,2?-bipy)_2(H_2O)_5]_2·3H_2O has been synthesized with MnSO_4·H_2O, 2,2?-bibenzoic acid (H_2L) and 2,2?-bipyridine(2,2?-bipy) in the mixed solvent ethanol and water. It crystallizes in monoclinic, space group P1 with a = 9.9944(10), b = 21.939(2), c = 25.628(3) A, α = 108.429(3), β = 100.613(4), γ = 102.821(3)o, V = 4997.9(9) A~3, D_c = 1.355 g/cm~3, Z = 2, F(000) = 2108, GOOF = 1.074, the R = 0.0626 and wR = 0.1531. The structure of the complex contains two [Mn_2(L)_2(2,2?-bipy)2] units, ten c...