Advances in Organic Synthesis is a book series devoted to the latest advances in synthetic approaches towards challenging structures. The series presents comprehensive reviews written by eminent authorities on different synthetic approaches to selected target molecules and new methods developed to achieve specific synthetic transformations or optimal product yields. Advances in Organic Synthesis is essential for all organic chemists in academia and the industry who wish to keep abreast of rapid and important developments in the field. This volume presents the following chapters:- “On Water” And “In Water” Strategies for Heterocyclic Transformations- Ionic Liquid Based Polyoxometalates as Functionalized Organic-Inorganic Hybrid Materials for Catalytic Organic Reactions- Recent Advances in the Synthesis and Bio-Applications of some Oxygen and Sulphur Containing Seven Membered Heterocyclic Compounds- Application of Nitriles on the Synthesis of 5-Membered Azaheterocycles: An Update from 2014 To 2020- The Role of Carbon-Based Solid Acid Catalysts in Organic Synthesis