Cation-π interaction is a potent intermolecular interaction between a cation and an aromatic system,
which has been viewed as a new kind of binding force, as being compared with the classical interactions
(e.g. hydrogen bonding, electrostatic and hydrophobic interactions). Cation-π interactions have
been observed in a wide range of biological contexts. In this paper, we present an overview of the typical
cation-π interactions in biological systems, the experimental and theoretical investigations on
cation-π interactions, as well as the research results on cation-π interactions in our group.