Hybrid inorganic-organic material based on Keggin type polyoxometalaes ([SiW₁₂O₄₀]^4-) and praseodymium-dipicolinic acid (pydc; 2,6-pyridindicarboxylic acid) with the formula of [Pr₂(pydc)₂(H₂O)₈][H₂SiW₁₂O₄₀]•4H₂O (1) is obtained under a hydrothermal condition. Compound 1 was characterized by infrared spectrum and elemental analysis and its structure was further determined by single-crystal X-ray diffraction. X-ray analysis illustrates the praseodymium atoms connect to each other through organic linkers to form four nuclear cycles. Two crystallographically independent four nuclear cycles are created by a rotation C2 axis. Through connection of these cycles, another two cycles in different orientation will formed which are bigger by 8 nodes. Finally, silicotungstate molecules accommodate up and down these cycles. This motif will expand regularly in all dimensions to construct a 3D coordination polymer accompanied by Keggin nano-particle guests.