For the first time, extraction process in ionic liquids was visualized by direct electron microscopy observation. Microscopy images revealed the micro-heterogeneous nature of the studied extraction systems. Depending on the nature of ionic liquids and studied compounds, four main systems were observed at micro-scale level: (a) uniform homogeneous phase; (b) microcompartments in the liquid phase; (c) solid microinclusions on the phase boundary; and (d) solid microinclusions inside the separated microphases. The microscopic monitoring showed the stepwise sequence of the extraction process, and the retention ability of the ionic liquid-water system decreased in the following order: homogeneous phase > micro compartments > solid microinclusions. (C) 2017 Elsevier B.V. All rights reserved.