Coordination polymers offer a significant potential for applications in adsorption, guest and anion recognition and sensing. 1 Their structure commonly provides binding sites for such specific interactions as π–π stacking and XH⋯π hydrogen bonding. 2 The latter reflects the ability of the π-cloud to interact with positively polarized atoms. An electrostatic interaction between anionic species and electron deficient heterocycles, which parallels the above binding scheme, is ...