The recycling of homogeneous catalysts is highly desirable from both an environmental and an economical point of view. However, the fact that catalysts and products are distributed homogeneously throughout the reaction mixture hampers catalyst separation. An elegant approach facilitating catalyst recovery is its immobilisation in a liquid support. Three solvent systems that have shown promise in this respect are fluorous biphasic solvent systems, supercritical carbon dioxide and ionic liquids. This thesis addresses the development of highly fluorous tetraarylborate anions which can be employed as such, or in combination with fluorous ligands, to enhance the solubility and performance of ionic catalysts in perfluorinated solvents and supercritical carbon dioxide. Furthermore, these anions have been used in the design of ionic liquids with unprecedented physical properties