This tutorial review describes the use of 2,2':6',2''-terpyridine (tpy) metal-binding domains in supramolecular chemistry. The origins of tpy chemistry are described and the reasons for its current importance in supramolecular chemistry are explained. Examples of tpy compounds in a wide variety of supramolecular chemistry are presented. The content will be of interest to organic, inorganic, supramolecular and nanoscale chemists.