The definition of ion pairing has evolved over time, driven by advances in our understanding of electrostatic interactions and molecular behaviour. Historically, ion pairing started with Bjerrum's pioneering work in 1926, where he proposed a definition based on the electrostatic work required to separate two ions. Subsequently, Anslyn and Dougherty introduced a physicalorganic definition in 2006, emphasising the spatial proximity and the energetic strength of the electrostatic attraction between ions. Their definition considers the comparison between the electrostatic energy and the thermal energy available for ion separation.