A new inorganic-organic hybrid, [DMAPM]+[CdI3]- (DMAPM+ = p-dimethyla- mino-1-methyl-pyridinium), has been synthesized by the reaction of [DMAPM]+I and CdI2, and characterized by IR and elemental analysis. The crystal structure was obtained via X-ray single- crystal diffraction with the following data: triclinic, space group P1, a = 8.0974(9), b = 9.6187(10), c = 10.5028(8) ? = 75.049(6), = 86.321(3), = 87.791(3)? V = 788.50(13) 3, Dc = 2.655 g/cm3, Z = 2, R = 0.0385 and wR = 0.0976. In the structure, one cadmium and four iodine atoms form a tetrahedral geometry, and two of such tetrahedra are connected in a co-line way to constitute Cd2I62 dimer. To our knowledge, this is the first example of dimerized CdI4 tetrahedron. All of the dimers are packed in the same mode, while the [DMAPM]+ cations are anti-parallelly arrayed. A new inorganic-organic hybrid, [DMAPM] + [CdI3] - (DMAPM + = p- dimethylamino-1 -methyl- pyridinium), has been synthesized by the reaction of [DMAPM] + I and CdI2, and characterized by IR The crystal structure was obtained via X-ray single-crystal diffraction with the following data: triclinic, space group P1, a = 8.0974 (9), b = 9.6187 (10), c = 10.5028 75.049 6 = 86.321 3 = 87.791 3 V = 788.50 (13) 3 Dc = 2.655 g / cm3 Z = 2 R = 0.0385 and wR = 0.0976 In the structure, one cadmium and four iodine atoms form a tetrahedral geometry, and two of such tetrahedra are connected in a co-line way to constitute Cd2I62 dimer. To our knowledge, this is the first example of dimerized CdI4 tetrahedron. All of the dimers are packed in the same mode, while the [DMAPM] + cations are anti-parallelly arrayed.