3,4-Dihydropyrimidin-2(1H)-ones derivatives were synthesized in moderate to high yields in one-pot three component reaction from the corresponding aldehydes, 1,3-dicarbonyl compounds and urea, Coconut shell char sulfonic acid (CSCSA) used as a reusable, and efficient catalyst. Compared to the classical acid catalyst, This new protocol for the Biginelli reaction includes the following important features: excellent yields, non-toxic, inexpensive and easily available reagent.