Novel halogen and phosphorus free ionic liquids containing chelated organoborate anions having different alkyl chain lengths and tetrabutyl ammonium cations have been studied as anti-wear and friction reducing agents under elasto-hydrodynamic/mixed lubrication conditions for steel–steel contacts. The synthesized ionic liquids were found to be quite stable at room temperature and showed a remarkable improvement in the friction-reducing and anti-wear properties of the PEG 200 lube base. The effect of alkyl chain lengths on the tribo-performance of the synthesized additives was systematically studied.