Graphene synthesis in a flash: Despite more than 15 years of exploration, the efficient and low-cost production of graphene, especially high-quality graphene, remains a great challenge. Very recently, a breakthrough in the synthesis of graphene materials was reported by Tour et al. It realized a super-fast synthesis of high-quality graphene at low cost, showing a great potential for commercialization.

The next generation: Recent developments made in the field of pillar[n]arene-based macrocyclic molecules to go beyond single macrocyclic structures with two alkoxy substituents on every benzene ring are highlighted. The recently introduced tiara[n]arenes, leaning pillar[n]arenes, and BowtieArenes with incomplete alkoxy substitution may be regarded as a next step in the structural diversification of pillar[n]arenes.

Excited deracemization: Visible-light photocatalysis has been utilized to convert racemates into single enantiomers in the presence of a chiral photosensitizer or a pair of chiral catalysts. Mechanistic studies revealed that energy transfer (E_nT) or a sequence of electron transfer (ET), proton transfer (PT), and hydrogen atom transfer (HAT) is operative.

Recent groundbreaking studies on organoferrates have demonstrated that coordinatively unsaturated three-coordinate-σ-alkylferrates are active catalysts in Fe-catalyzed cross-couplings with Grignard reagents and that pronounced solvent and counterion effects dictate metalate speciation and catalyst activity. Thanks to modern spectroscopic methods, sensitive catalyst intermediates could be analyzed.

Leaving graphitic flatland: The atomically precise synthesis of graphitic nanocones was achieved by bottom-up synthetic methods. This advancement provides access to a new class of discrete nanocarbons and, with that, unlocks opportunities in the field of three-dimensional graphitic architectures amenable to molecular design.

Flattened: A six-coordinate [ML₃Z₃]-type transition-metal complex with a hexagonal planar geometry has been isolated and characterized, extending the scope of six-coordinate metal coordination compounds to those with a geometry beyond octahedral and trigonal prismatic.

The Nobel Prize in Medicine or Physiology 2019 was awarded for discoveries of how cells sense and adapt to oxygen availability. This Highlight acknowledges the impact of the laureates’ contributions and summarises the history, molecular aspects, and current challenges of research on how oxygen regulates gene expression. Opportunities for molecular scientists in the field of macromolecule hydroxylation are emphasised.

On to the next alkaline-earth metal: The new electrolyte calcium bis-tetrakis(hexafluoroisopropyloxy)borate, Ca[B(hfip)₄]₂, is highlighted for its capability of reversible Ca deposition/stripping at room temperature, giving hope for the development of Ca batteries in the foreseeable future.

The main-group age: The past decade has revealed main-group-element compounds that display transition-metal-like reactivity in stoichiometric and even catalytic transformations. Cornella and co-workers have now reported a bismuth complex that catalyzes fluoroarene formation from aryl boronate esters, a reaction that is almost unprecedented in transition-metal catalysis.

Impressive developments in the direct C−H bond borylation of (hetero)arenes have been achieved in the past decades. The applied catalysts are shifting from noble metals to metal-free systems. This Highlight gives a brief summary of this evolution and focuses on recent elegant work in this field.

Mitsunobu revisited: The use of (2-hydroxybenzyl)diphenylphosphine oxide as an efficient catalyst has recently enabled the development of a catalytic redox-neutral Mitsunobu reaction. This reaction constitutes the first intermolecular stereospecific substitution of non-allylic alcohols where only water is formed as a by-product.

E-merging methods: The merging of a homogeneous photocatalytic system with an electrochemical cell has been recently applied to organic synthesis, allowing to realize net-oxidative photocatalytic processes in the absence of a chemical oxidant.

AI for chemistry: Automated synthesis can now be performed using an artificial intelligence algorithm to propose the synthetic route and a robotic microfluidic platform to execute the synthesis. This Highlight describes this approach towards small-molecule synthesis and reflects on the significance of this milestone in chemistry.

A Y₂Ti₂O₅S₂ oxysulfide photocatalyst that is activated and stabilized by Rh/Cr₂O₃ and IrO₂ co-catalysts achieves efficient photocatalytic overall water splitting when irradiated with 600 nm visible light. The band gap of Y₂Ti₂O₅S₂ is a narrow 1.9 eV because Y 3d contributes to the valence band maximum. This Highlight discusses this recent innovation in sulfide-based photocatalytic materials. Key: conduction (CB) and valence (VB) bands, hydrogen (HEC) and oxygen (OEC) evolution co-catalysts.

Lab in a droplet: Rapid condensation reactions between aldehydes and indoles can be performed efficiently with a high-viscosity solvent in liquid marbles since the mixing of the reagents is induced by an external electric field. This strategy complements other stimuli, such as magnetic field and acoustic waves, and thereby opens a new avenue for dual- and multi-component miniaturized chemical reactions.

Significant progress in C−C bond activation with transition metals has recently enabled the development of several carbon isotope exchange reactions. These methods are based on C−C bond decarboxylative carboxylation reactions in the presence of selected transition metals and labelled carbon monoxide or carbon dioxide.

N-Heterocyclic carbene (NHC) catalyzed reactions that proceed through radical pathways are summarized in this Highlight, with a particular focus on a recent contribution from Ohmiya and co-workers on the coupling of aldehydes with alkyl radicals.

Polymethine bridges in cyanine dyes may be constrained by setting them into edge-fused ring systems, or extended by conjugation with carefully chosen heterocycles. Recent studies have shown that modifications like these can give significantly brighter dyes with red-shifted absorbance and emission maxima.

The C−F functionalization of acid fluorides has recently emerged as a new disconnection in transition-metal catalysis. Selective decarbonylative and non-decarbonylative transformations are presented together with first evidence on ligand-controlled selectivity.

Radical developments: Photochemical/secondary amine dual catalysis has proven to be an efficient strategy for radical umpolung reactions. Two new processes provide an elegant solution to a long-standing chemoselectivity problem for the synthesis of 1,4-dicarbonyl compounds.