One dimensional chain cadmium (11) coordination polymer has been synthesized with 2,4,6-trimethylbenzoic acid, 1,10-phenanthroline and cadmium perchlorate anhydrous in the solvent mixture of water and methanol. Crystal data for this complex: Tetragonal, space group I4(1), a=2.042 5(7) nm, c=1.395 2(5) nm, V= 5.820(3) nm(3), D-c=1.454 g.cm(-3), Z=8, F(000)=2 608, GooF=1.064, R-1=0.034 8, wR(2)=0.070 4. The crystal structure shows that the Cobaly ion is coordinated with two nitrogen atoms of one 1,10-phenanthroline molecules and four oxygen atoms from two 2,4,6-trimethylbenzoic acid molecules and one water molecule respectively, forming a distorted octahedral coordination geometry. The result of TG analysis shows that the title complex was stable under 240.0 degrees C. CCDC: 665256.