Unorthodox Interactions at Work.

This Perspective elaborates on the currently unfolding interest in integrating unorthodox non-covalent interactions into functional systems. Initial emphasis is on anion-π interactions at work, particularly in catalysis. Recent highlights are described in comparison to a coinciding renaissance of the more conventional, charge-inverted cation-π catalysis. Progress with these complementary aromatic systems is then compared to recent efforts to integrate halogen and chalcogen bonds, the unorthodox counterparts of hydrogen bonds, into functional systems. General focus is on catalysis, pertinent examples on self-assembly, transport, sensing, and templation are covered as well.