Abstract The upstream petroleum industry faces operational and technical challenges due to the production of crude oil containing waxes, asphaltenes and aromatic compounds and also due to the formation of gas hydrates resulting in their deposition in the surface and production equipments and in offshore pipelines affecting the safer operations, in turn resulting in huge production losses, and threatening the environment. It is also estimated that, all over the globe there are more than double the times of reserves of heavy and extra-heavy crude oil than the lighter one. As the world's demand for light crude oil continues to increase tremendously, the supplies of these easily extractable crude oil continues to decrease although efforts have already been made to extract the heavy and extra-heavy oil that was previously considered uneconomical to produce and process. The main aim of this investigation is to finding greener-environmentally friendly methods for oil and gas industries, such as the use of aromatic and aliphatic based ionic liquids for the efficient dissolution of tank-bottom sludge, heavy crude oil and pipeline wax deposition. Ionic liquids, therefore, have a tremendous scope in the application of oil recovery by assisting in recovering valuable crude oil from the oily sludge which is otherwise lost due to dumping and burning. Moreover, the ionic liquids used could be recovered and can be recycled and reused several times. The enhancement in the solubility of heavy crude oil in solvent and ionic liquids mixture is investigated using UV-Visible, FT-IR and 13C-NMR spectroscopic techniques. It is observed that, the dissolution of heavy crude oil is more in the solution with ionic liquid than with the solvent alone. Solubility of heavy crude oil in the presence of studied ionic liquids and in the studied solvents increases about 65 %, when compared with the solutions of heavy crude oil in solvents without ionic liquids. The application of this method could also helps in the highly essential enhanced oil recovery industry.