This review deals with the catalytic application of ionic transition-metal complexes using different ionic liquids as solvents. Additionally, so-called organometallic ionic liquids have been described with regard to their activity in several types of reaction. In most cases the catalysis was additionally performed under homogeneous conditions allowing a comparison between the use of ILs and conventional organic solvents. In all described cases the biphasic performance led to a higher recyclability of the catalytic system.