Herein, we studied the absorption of H2S and CO2 in 1-methylimidazolium bis(2-ethylhexyl) sulfosuccinate ([mim][doc]) and 1-buthyl-3-methylimidazolium bis(2-ethylhexyl) sulfosuccinate ([bmim][doc]) at various temperatures and partial gas pressures. The choice of the [doc] anion was determined by the ability of bulky moieties along with the polar functional groups to enhance the solubility of acidic gases, as confirmed during the volumetric measurements of gases solubility. It was shown that the protic cation presence determines a significant reduction of the CO2 and H2S solubilities as well as the thermal stability of ILs. There were found that [bmim][doc] tends to have higher absorption capacity toward acidic gases compared with [mim][doc]. The solubility of hydrogen sulfide, characterized by the Henry's Law constant, in [bmim] [doc] and [mim][doc] turned out nearly 4-5 and 1.5-2 times higher than in conventional ionic liquids respectively. (C) 2018 Elsevier Ltd.