The present disclosure provides an ionic liquid comprising at least one nitrogen containing Lewis base, at least one Bronsted acid and at least one metal salt, wherein the nitrogen containing Lewis base is selected from the group consisting of urea, amides, cyclic 5- membered-ring amides, cyclic 6-membered-ring amides, amines, cyclic 5-membered-ring amines, and cyclic 6-membered-ring amines. The ionic liquids of the present application are prepared from inexpensive, and environment-friendly components by a simple process. The ionic liquids of the process of the present disclosure can be used for alkylation, trans-alkylation, acylation, Diel-Alder reaction, Friedel-Crafts reaction, and oligomerization.
