In this paper, the synthesis of arylidene heterobicyclicpyrimidinones and thiones is reported by condensation of aromatic aldehydes, cyclopentanone, and urea or thiourea in the present of FePO4 as the green and recyclable catalyst. Using solvent-free conditions, non-toxic and inexpensive materials, simple and clean work-up, relatively short reaction times, and high yields of the products are the advantages of this method. Also, some new derivatives of arylidene dihydropyrimidinones and thiones were prepared by this green method.