Worries have arisen in the area of chemical processing due to huge quantities of inflammable and toxic solvents are used every day. Continuous use of solvents has a harmful effect on all living plants and animals, destroying most organs. In spite of the fact that organic solvents, like acetone, DMSO, DMF as well as aromatic compounds e.g. benzene, toluene and chlorinated solvents contribute to the environmental pollution, they are still used in large amounts. The most important intention of green chemistry is to decrease the use of solvents or substituting them with less toxic ones. Ionic liquids, water, supercritical fluids, non-toxic liquid polymers like PEG are part of the class of green solvents. They are classified by convenient accessibility, low toxicity and option of reuse. Among all, ionic liquids (ILs) are most popular among all scientists because of their versatile behavior like: high stability, biodegradability, low vapor pressure and low toxicity etc. Due to these properties ILs are the best replacement of traditional chemicals and reflected as green solvents. The present review article mainly emphasizes on different types of ILs and their role in environmental pollution control and also in medical applications.