We propose a comparative study of the high-frequency optic-like mode and Boson peak modes observed in the vibrational density of states (DOS) in the glass phase of the two model ionic liquids 1buthyl-3-methylimidazolium chloride ([C4MIM]Cl) and 1buthyl-3-methylimidazolium bromide ([C4MIM]Br) by means of Inelastic Neutron Scattering (INS). Aim of the experiment is to obtain a first experimental analysis of the correlation (if any) between boson peak modes and concentration fluctuations dynamics in ionic systems. Moreover we aim at obtaining for the first time an experimental characterization of differences in behavior of the high-frequency optic-like mode in liquids and glasses.