A novel aromatic tricarboxylic acid of 4,4 '-(2-carboxypropane-1,3-diyl)dibenzoic acid (H3L) was used to prepare two Mn-II complexes of [Mn-3(L)(2)(bpy)(2)](n) (1) and [Mn-3(L)(2)(phen)(2)](n) (2), where bpy = 2,2 '-bipyridine and phen = 1,10-phenanthroline. The single crystal structures, thermal stability, and the magnetism of 1 and 2 were measured and discussed in this article. According to the magnetism measurements, the Curie constants and the Weiss constants should be 12.29K center dot cm(3)center dot mol(-1) (g = 1.94, S = 5/2) and -9.80K for 1 and 11.11K center dot cm(3)center dot mol(-1) (g = 1.83, S = 5/2) and -9.26K for 2, respectively.