The absorption spectra of 1-bulyl-l-mellylimidazolium hexafluorophosphate ([bmim] [PF6]) and 1-methyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide ([bmim][TFSI]) were measured. The similarity of the spectra in the liquid phase with the corresponding solution spectra shows that weak electronic intermolecular interaction occurs in these ionic liquids.