This front cover illustrates the work by Marcel Mayor, at the University of Basel, Switzerland, and colleagues on the synthesis, characterisation and tunable Förster energy transfer (FRET) properties of planar chiral asymmetric naphthalenediimide (NDI) cyclophanes. They controlled the extent of intramolecular FRET by varying the core substituents of only one deck of the NDIs. 

Zhan-Ting Li, at the Chinese Academy of Sciences, Shanghai, and colleagues, used intramolecular hydrogen bonding to induce the U-shaped conformation of precursors and promote the formation of macrocyclic architectures through click chemistry. Their work is illustrated on the inside front cover.

In the Perspective, Andreas Herrmann, from Firmenich in Geneva, Switzerland, discusses imines as probes for molecular evolution at the interface between chemistry and biology.

The Hot Article, by Richard Hsung and colleagues, at the University of Wisconsin, Madison, US, describes the development of an easy, direct route to amino-spiro[2,2]pentanes that could be used in drug discovery.