In this issue, K. Pu et al. review hemicyanine-based near-infrared activatable probes for imaging and diagnosis of diseases. What are the current design strategies of such probes? The Minireview deals with interfaces and interfacial layers in inorganic perovskite solar cells (W. Tress et al.).

In the original research section, J. Gascon et al. describe an efficient metal–organic framework-derived nickel catalyst for the light-driven methanation of CO₂. K. Nozaki et al. present high-density polyethylenes bearing isolated in-chain carbonyls. Z. Chen et al. engineered oversaturated Fe–N₅ multifunctional catalytic sites for durable lithium–sulfur batteries (see picture). J. K. Stolarczyk et al. created a multi-layer device for light-triggered hydrogen production from alkaline methanol.

• Angewandte Chemie 51/2021: Design Strategies,
  Angew. Chem. Int. Ed. 2021, 60 (51).