Rare earth complexes of Eu³⁺ and Nd³⁺ with pyridine dicarboxylate [Ln(2,6?dipic)(2,6?Hdipic)(H₂O)₂]?4H₂O (Ln: Eu, Nd) were synthesized by hydrothermal method. The structure, magnetism and thermodynamic properties of the complexes were studied by the means of single crystal X?ray diffraction measurement, magnetic test, thermogravimetric analysis and differential scanning calorimetry analysis. The results show that two complexes are isostructural crystallizing in the monoclinic system of space group P2₁/c. There are two different coordination modes for pyridine?2,6?dicarboxylic acid in the crystals. The complexes exhibit antiferromagnetism with obvious orbital coupling effect. The prepared complexes have good thermal stability.