The ionic liquid (IL) (1-methyl-4-ethyl pyridine-1-ium iodide) [MEPy]I in this work was created through a direct reaction between 4-ethyl pyridine and methyl iodide. Subsequently, complex salts were prepared using Lewis acids (ferrous chloride and copper chloride) in molar ratios of 1:1 and 1:2, ionic liquid: metal chloride. Nuclear magnetic resonance spectroscopy 1H-NMR, elemental analysis (CHN), infrared spectra FT-IR, and other methods were used to identify the prepared compounds. Moreover, the study of the thermal stability of the prepared compounds. These compounds were tested in the extractive desulfurization process (EDS). Using a model oil sample containing dibenzothiophene (DBT) as an aromatic organosulfur compound dissolved in solvent (n-decan) at a concentration of 1500 ppm. The sulfur percentage was estimated before and after treatment by gas chromatography technique GC-FID, and the conditions were determined (time and concentration of the extracted substance), as it was found that ionic liquids of pyridine base and its complex salts with ferrous and copper chlorides have good efficiency in the process of removing sulfur (EDS).