The unique characteristics of ionic liquid (IL) that can be tailored-made to its application make it a distinctive substance for broad applications. It is also considered as an excellent alternative and known as a green solvent, which is thermally stable and has almost negligible vapor pressure. The main objective of the study is to give an overview of the properties of ionic liquids that possess high gas absorptivity and to study the effect of ionic liquid on the characteristics and performance of membranes. This includes incorporating the ionic liquids in membranes, gas solubility mechanism through the ionic liquids, the achievement using the ionic liquid in membranes gas separation, and the gas transport through membranes containing ionic liquids. Furthermore, issues and challenges were identified and highlighted for future developments. © 2020, Institute of Chemistry, Slovak Academy of Sciences.