A process for the halogenation of an aromatic compound wherein the aromatic compound is admixed with a halogenating agent in the presence of an ionic liquid is described. The method in preferably halide, sulfur or nitrate ionic liquids has significant advantages over conventional halogenation reactions. These are that the reaction starts with, e.g., a halide salt rather than, e.g., a halogen, and is therefore more convenient and safer. Also, when the reaction is performed in a nitrate ionic liquid, the only by-product is water.