Since the synthesis of the first arene ruthenium complexes in 1967, various groups have systematically investigated the chemistry of this family of complexes because of their appealing structural diversity, related to the ways in which the arene ligand can be functionalized, their role as versatile stereochemical controlling elements in areas such as catalysis, chemical and photochemical sensing, biology and supramolecular chemistry, and their potential as metalloligands. This review is focused on the recent developments of arene ruthenium complexes towards both supramolecular chemistry and biology. Arene ruthenium complexes can form various supramolecular structures with applications as chemical/photochemical sensors, in medicine and for drug transport inside the cell. Recent developments in the chemistry of arene ruthenium complexes will likely give access to a variety of metal-based drugs/sensors within the next few years.