Ionic liquids (ILs) are attracting increasing interest as a potential ecosustainable alternative to traditional volatile organic solvents (VOCs), generally used in large amounts. About the “greenness” of ILs a certain controversy still exists because their toxicity and biodegradability need to be fully assessed. Moreover, the real advantages of using this novel class of solvents should be more deeply studied in comparison with traditional media. This article presents some of the most recent findings in this field by reviewing selected examples of applications of ILs in organic synthesis and catalysis. In addition, anionic reactivity data for some organic reactions will be discussed and compared with those previously found for the same reactions in molecular solvents. Finally, updated results concerning toxicity, ecotoxicity and biodegradation of the most common ILs will be reported.