The synthesis, crystal structure, and properties of [M(Pi)(MCPA)(2)(H2O)(2)](n) (MCPA = 2-methyl-4-chlorophenoxyacetic acid), 1, a 2-D manganese carboxylato polymer is reported. The synthesis of 1 has been achieved via the reaction of MCPA with MnCl2 . 2H(2)O and NaHCO3 in methanol. Crystal structure data : [C18H2OCl2O8Mn]; orthorhombic; space group Pbca; a = 7.811(6) Angstrom; b = 34.67(3) Angstrom; c = 7.481(6) Angstrom; Z = 4. The compound has a two-dimensional structure with Mn2+ atoms in an octahedral environment and mixed water/carboxylate coordination. The metal atoms are segregated in planes which are perpendicular to the b axis and are spaced 17.73 Angstrom apart. Variable-temperature magnetic susceptibility measurements indicate the presence of antiferromagnetic behavior. The EPR spectra of polycrystalline samples at 4 K show that the intensity of the signal decreases significantly with decreasing temperature and below similar to 4 K becomes EPR silent.