The associative interaction between resin‐bound polybrominated arenes and small molecules was analyzed by using various spectroscopic techniques as well as a synthetic molecular model to establish the thermodynamics. The binding in acetonitrile was three orders of magnitude stronger than that in methanol, partly owing to the tertiary conformational gating of the resin that controls the entropic terms. By using the entropic superiority, the associative binding of up to 3×104 m−1 is achieved with the non‐biological system. A modified Hill plot for the quantitative analysis of bindings was also devised, which enabled the interactions at the molecular level to be elucidated.

The front cover shows the associative interaction between polybrominated arenes immobilized onto the surface of a resin and small molecules having a diphenylurea backbone. In this system the association and dissociation of the small molecules depends strongly on the particular solvent and on entropy. Understanding and controlling such noncovalent interactions is important for devising sophisticated systems for separation and detection applications. Details are given in the Communication by M. Yamamoto and co‐workers on page 820 in Issue 9, 2018 (DOI: 10.1002/cplu.201800304).