In this issue, G. Evano and C. Theunissen review innate alkylations of C–H bonds in arenes. What alternatives are there to Friedel–Crafts reactions? The Minireviews deal with piezoelectric semiconductors for enhanced catalytic activities (Z. Lin et al.), catalytic metallopolymers from [2Fe-2S] clusters as artificial metalloenzymes for hydrogen production (J. Pyun et al.), and the chemistry of layered pnictogens phosphorus, arsenic, antimony, and bismuth (M. Pumera et al.).

In the Communications section, X.-Y. Cao et al. investigate stable diindeno-fused corannulene regioisomers with open-shell singlet ground states and large diradical characters (see picture). M. Armand et al. report enhanced lithium-ion conductivity of polymer electrolytes by selective introduction of hydrogen into the anion. Z. Tang et al. present biomimetic chiral photonic crystals, and M. Yamashita et al. describe a monomeric stannabenzene.

• Angewandte Chemie 23/2019: Alternatives,
  Angew. Chem. Int. Ed. 2019, 58 (23).