In the last two decades, considerable attention was devoted to the use of ionic
liquids (ILs) in organic syntheses. Initially, they were applied as solvents, often playing
the role of the catalyst as well. Nowadays, there is a growing trend to apply the ILs as cosolvents,
additives, or catalysts in organic reactions. The spread of ILs justified several
reviews on reactions carried out in the presence of different ILs. However, there is no
sharp line between the cases, when the IL is used as a solvent, or only as a catalyst. This
review aims at summarizing the examples of organic syntheses promoted by a catalytic
amount of an IL, and highlighting the typical IL-catalyzed reactions.