Heterocyclic nucleus forms the basic of most of the medicinal compounds. Instead of using classical method. It is proposed to carry out the synthesis of heterocyclic compounds by ring transformation that may involve ring contraction, ring retention and ring expansion in five, six and seven membered heterocycles containing oxygen, sulphur and nitrogen. Special attention would be paid to apply the principles of green chemistry while carrying out these ring transformations e.g., choice of safer reagents, use of green catalysts and phase-transfer catalysts whenever necessary. Here a new solid support, Zinc oxide is used. Employing microwave incluced synthesis whenever possible, minimizing the use of toxic solvents. Benzofurans have been achieved from coumarins by ring contraction reaction in single step. Microwave irradiation has been used to shorten the reaction time and to improve the yield