In summary, we have conducted a DFT study to investigate the complexation phenomena of RE cations, Nd(III) and Yb(III), with [MMI][PF6] in RTIL. Although the solvation mechanism of the RE cations in RTILs is fairly studied using MD simulations, there is hardly any work focusing on this interaction at a molecular level. Here, we have considered the formation of the first solvation shell through the direct bonding between Ln(III) and PF6 -, followed by a second solvation shell formed by cationic [MMI] + .