Two new manganese complexes, [Mn 3 (L 1 ) 4 (NO 3 ) 2 ] n (1, HL 1 =nicotinate N-oxide acid) and [MnL 2 Cl] n (2, HL 2 =isonicotinate N-oxide acid)], have been hydrothermally synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. In 1, the L 1 ligands take two different coordinated modes bridging four and three Mn II ions. The nitrate anions take chelating coordination modes, leading one type of the Mn II ions as a 4-connected node. The whole net can be viewed as a 3, 4, 6-connected 4-nodal net with Schläfli notation {4 3 }2{4 4 ; 6 2 }4{4 6 ; 6 6 ; 8 3 }. Complex 2 has a honeycomb layer mixed bridged by chlorine, N-oxide and carboxylate. The adjacent layers are linked by the phenyl ring of L 2 ligand, giving a 3D framework with a {3 4 ; 5 4 } {3 2 ;4;5 6 ;6 6 } 4, 6-connect net. Magnetic studies indicate that 1 is an antiferromagnet with low-dimensional characteristic, in which a –J 1 J 1 J 2 – coupled alternating chain is predigested. Fitting the data of 1 gives the best parameters J 1 =−2.77, J 2 =−0.67cm −1 . The magnetic properties of complex 2 represent the character of the 2D honeycomb layer with the J 1 =−2.05 and J 2 =0.55cm −1 , which results in a whole antiferromagnetic state.