A novel Co-glutarate, Co[O2C(CH2)(3)CO2] (1), Was synthesized as single crystals by the hydrothermal reaction of CoCl2 with glutaric acid in the presence of KOH and characterized by single-crystal X-ray diffraction analysis, TGA, IR, UV-vis reflectance spectrometry, and SQUID measurements. The dark purple Co-glutarate crystallizes in the monoclinic system in the space group P2/c, with a = 14.002(3) Angstrom, b = 4.8064(10) Angstrom, c = 9,274(3) Angstrom, beta = 90.5(2)degrees, and Z = 4. The CO2+ centers are tetrahedrally coordinated to four oxygen atoms from the dicarboxylate ligands. The anhydrous-pillared three-dimensional structure consists of infinite Co-CO2-Co inorganic layers, which are stacked by the coordinated glutarate alkyl chain along the a-axis. There are two different conformations for glutarate ligands, i.e,, the gauche- and the anti-forms. These ligands reside between the inorganic layers alternatively to separate each layer by 7.01 Angstrom (gauche) and 6.99 Angstrom (anti). Magnetic measurement reveals that the predominant magnetic interactions are antiferromagnetic below 14 K.