Two novel manganese(II) tetrazolate coordination polymers, Mn-3(Hbta)(4)(mu-2OH)(2)(H2O)center dot 2H(2)O (1) and Mn(bta)(H2O) (2), were obtained by the hydrothermal reaction of MnCl2 center dot 4H(2)O with N,N-bis[l(2)H-tetrazol-5-yl]amine (H(2)bta) in different pH values, Compound 1 exhibits a 2-D (4,4) layer structure, which is built from binuclear Mn-2(mu(2)-OH)(2) subunits and mu(3)-bridging Hbta(-) linkers. Compound 2 is a helical framework, and its 3-D PtS-like net is constructed by Mn-2(bta)(2) dimers and mu 5-bridging bta(2-) linkers. Magnetic measurements reveal that compound 1 displays an antiferromagnetic ordering, while compound 2 exhibits the coexistence of a spin-canted antiferromagnetic coupling and a field-induced spin-flop transition.