ZnO/MgO Containing ZnO Nanoparticles as a Highly Effective Heterogeneous Base Catalyst for the Synthesis of 4H-Pyrans and Coumarins in [bmim]BF4

4H-Pyrans and coumarins were synthesized through one-pot reactions using ZnO/MgO solid sample containing ZnO nanoparticles as an efficient reusable catalyst in ionic liquid, [bmim]BF4. The catalyst is inexpensive and easily obtained, stable and storable, easily recycled and reused for several cycles with consistent activity. The procedure offers advantages in terms of higher yields, short reaction times, and mild solvent-free reaction conditions.