In this issue, J. I. Seeman et al. review the evolution of the Diels–Alder reaction mechanism since the 1930s, and K. Pu et al. summarize electromagnetic nanomedicines for combinatorial cancer immunotherapy. The Minireviews deal with iodine redox chemistry in rechargeable batteries (J. Zhang et al.) and transient covalent bonds in abiotic nonequilibrium systems (C. S. Hartley et al.). In a Highlight, R. Murugavel et al. discuss the redox chemistry of ferrocene.

In the original research section, T. Haino et al. describe the self-assembly of nanographenes (see picture). J. G. Hernández et al. observed mechanochemical prebiotic peptide bond formation. P. Nemes et al. advanced single-cell mass spectrometry to enable dual characterization of proteins and metabolites in frog embryo cells. P.-T. Puno et al. succeeded in the structure elucidation and scalable chemical synthesis of (−)-isoscopariusin A, a natural immunosuppressive meroditerpenoid.

• Angewandte Chemie 23/2021: Iconic Chemistry,
  Angew. Chem. Int. Ed. 2020, 60 (23).