A simple and highly efficient protocol for synthesis of flavones from 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in presence of ZnO nanoparticles as a promoter in thermal as well as microwave irradiation under solvent-free conditions have been demonstrated. The catalyst is inexpensive, stable, can be easily recycled/reused for several cycles with consistent activity and observed almost same yield confirming the stability of the catalyst. It is believed that the present approach will become an alternative route for the conventional reactions. Because in this protocol, yield is quite high, short reaction time, simple work up, catalyst can be recycled as well as it is free of any hazardous by-products formation during workup.