This book introduces some basic and advanced studies on ionic liquids in the electrochemical fi eld. Although ionic liquids are known by only a few scientists and engineers, their applications ’ potential in future technologies is unlimited. There are already many reports of basic and applied studies of ionic liquids as reaction solvents, but the reaction solvent is not the only brilliant future of the ionic liquids. Electrochemistry has become a big fi eld covering several key ideas such as energy, environment, nanotechnology, and analysis. It is hoped that the contributions on ionic liquids in this book will open other areas of study as well as to inspire.