The oxidation of alcohols has been of great value in organic synthesis and represents an important entry to essential functional groups, such as ketones, aldehydes, and carboxylic acids. Many standard oxidation procedures have been available for this purpose; nevertheless, reactions currently used to oxidize alcohols employ toxic chromium oxide. Many industrial oxidation reactions are currently performed with stoichiometric amounts of oxidants such as peroxides, nitric acid and high metal oxides. Thus, there is a constant need to develop inexpensive oxidants, preferably under catalytic conditions, to minimize inevitable co-products, which represents an environmental problem. The designing of such oxidation system remains a challenge; ideal catalytic oxidation reactions should operate at room temperature in an environmental friendly solvent system, e.g. water and use green co-oxidants, such as oxygen (air) or hydrogen peroxide.This book brings an insight on such green, environmentally benign processes involving transition metal complexes in Ionic liquids which are recyclable and reusable.