A novel pentadecatungstate, [H6Ce2(H2O)Cl(W5O18)(3)](7-) (1), constructed by a dinuclear cerium unit and 15-member ring WO6 units was prepared and characterized by single-crystal X-ray diffraction. Polyanion 1 exhibits blue photoluminescence with an emission maximum at 488 nm, which is characteristic of cerium(Ill) transitions from 5d to F-2(5/2) states. Furthermore, the study of the electrochemical property investigation of 1 shows two reversible redox peaks ascribing to two-electron processes.