Three new compounds, [Cd(μ3-Hpdh)(μ2-Cl)]n (1), Mn(Hpdh)2(H2O)2 (2) and Zn(Hpdh)2 (H2O)2 (3) (H2pdh = pyridine-2,3-dicarbo-2,3-hydrazide), have been synthesized and characterized by elemental analysis, IR spectra, TG and single-crystal X-ray diffraction. Under hydrothermal conditions, H2pdh is generated by an in situ acylation of H2pda (H2pda = pyridine-2,3-dicarboxylic acid) with hydrazine hydrate. Complex 1 features a 2D layer structure constructed by a dinuclear Cd(II) building block. In complexes 2 and 3, hydrogen bonding interactions connect mononuclear structures into 3D supramolecular frameworks.