One pot multi-component synthesis of heterocyclic bioactive Oxazine derivatives has been demonstrated by using catalyst Silicotungustic acid under microwave irradiation. The Oxazine derivatives are prepared using ethanol and water solvent in 9:1 ratio. The reactions are very fast and high yielding (~ 84-92 % product yield) within few minutes. The catalyst is easily isolated at the end of the reaction by simple filtration technique. The catalytic activity remains unchanged till the 7th cycle. The key advantage of this reaction is green reaction media aq. ethanol and rapid reaction time reusable catalyst and eco-friendly route using microwave irradiation.