Abstract: In the present study, we have accomplished N, N’-dimethyl formamide (DMF)/Trichloroisocyanuric acid and DMF/Trichlorotriazine as efficient catalysts for the synthesis of 3,4-dihydropyrimidinones/thiones from one-pot multi-component reaction of β-ketoester, aromatic aldehydes, and urea under reflux condition. The reaction operates also under solvent free microwave condition. The results obtained from this study were compared with those obtained from classical Vilsmeier Haack adducts (DMF/POCl3, and DMF/SOCl2) as catalysts. Reaction times and product yields observed in this study indicated shorter reaction times and better product yields with modified VH reagents (TCCA/DMF and TCTA/DMF) over classical VH reagents (POCl3/DMF, and SOCl2/DMF). The catalytic activity of (TCTA/DMF) > (TCCA/DMF) >(POCl3/DMF> SOCl2/DMF).