Cyanostar (CS, Figure ) is a pentagonal anion-binding macrocycle first reported in 2013. It is one of a class of planar and shape-persistent macrocycles that have five-fold symmetry, and a subset of C5-symmetric macrocycles with different shapes like the tubular pillar arenes. Since its debut, cyanostar has provided both reliable and novel anion binding properties, relying on high-fidelity recognition of anions (X -) as 2:1 complexes and as higher order systems, e.g. 2:2 complexes. 2