Metal-ligand interactions have emerged as an important tool to trigger and modulate self-assembly, and to tune the properties of the final supramolecular materials. Herein, we report the metal-cation induced self-assembly of a pyrene–peptide conjugate to form hydrogels. The peptide has been rationally designed to favor the formation of β-sheet 1D assemblies and metal coordination through the Glu side chains. We studied in detail the self-assembly process in the presence of H⁺, Li⁺, Na⁺, K⁺, Ca²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Co²⁺, Fe³⁺, and Cr³⁺ and found that the morphology and mechanical properties of the hydrogels are ion-dependent. Moreover, thanks to the presence of the metal, new applications could be explored. Cu²⁺ metallogels could be used for amine sensing and meat freshness monitoring, while Zn²⁺ metallogels showed good selectivity for cationic dye adsorption and separation.

The semi‐hydrogenation of acetylene in ethylene‐rich gas streams is a high‐priority industrial chemical reaction for producing polymer‐grade ethylene. Traditional thermocatalytic routes for acetylene reduction to ethylene, despite progress, still require high temperatures and high H₂ consumption, possess relatively low selectivity, and use a noble metal catalyst. Light‐powered strategies are starting to emerge, given that they have the potential to use directly the abundant and sustainable solar irradiation, but are ineffective. Here an efficient, >99.9% selective, visible‐light powered, catalytic conversion of acetylene to ethylene is reported. The catalyst is a homogeneous molecular cobaloxime that operates in tandem with a photosensitizer at room temperature and bypasses the use of non‐environmentally friendly and flammable H₂ gas feed. The reaction proceeds through a cobalt‐hydride intermediate with ≈100% conversion of acetylene under competitive (ethylene co‐feed) conditions after only 50 min, and with no evolution of H₂ or over‐hydrogenation to ethane. The cobaloxime is further incorporated as a linker in a metal–organic framework; the result is a heterogeneous catalyst for the conversion of acetylene under competitive (ethylene co‐feed) conditions that can be recycled up to six times and remains catalytically active for 48 h, before significant loss of performance is observed.

Self‐assembled organic chromophores form nanostructures in solutions, with their molecular packing determining the optoelectronic properties and photocatalytic activity. Here an organic dye molecule is reported, 1,3,6,8‐tetrakis(4‐ethynylbenzoic acid)pyrene (TEBAPy), that exhibits two aggregate states in aqueous conditions: nanofibers or nanoparticles, depending on the charge‐screening conditions. The nanofibers promote sacrificial photocatalytic hydrogen production (H ₂ , 84 mmol g ⁻¹ h ⁻¹ ) while the nanoparticles produce hydrogen peroxide (H ₂ O ₂ , 85 mmol g ⁻¹ h ⁻¹ ). Using a combination of structural and photophysical characterizations, it is shown that the photocatalytic activity is determined by the nature of the formed self‐assembled aggregate, demonstrating the potential of supramolecular nanostructures to tune their activity and switch their reactivity. It is shown clear correlation between the presence of fibrous nanostructures and photocatalytic H ₂ evolution, with spectroscopy showing mixing of excitonic states that enables efficient charge separation over multiple chromophore units. In the nanoparticular aggregates, on the contrary, the excitation is localized and leads to excimer formation that is involved in H ₂ O ₂ production. The results demonstrate that the molecular packing of a single chromophore in self‐assembled organic nanostructures can not only optimize solar fuel production but also enable multiple and switchable photocatalytic functions.

Light‐powered strategies for the semi‐hydrogenation of acetylene to ethylene are rapidly emerging as sustainable alternatives to the traditional thermochemical processes. The development of a robust, selective, as well as recyclable, non‐noble catalyst that can be powered by visible light and uses water as proton source to accomplish this important reaction remains a key challenge. Here the first demonstration of a cobalt single‐atom catalyst supported on carbon‐nitride (Co−CN) as an all‐in‐one photocatalyst for the semi‐hydrogenation of acetylene to ethylene is reported using water as the proton source, offering advantages over current hydrogenation technologies. Carbon nitride hosts the individual catalytic active sites of cobalt thus combining photosensitizer and cocatalyst in one unit, in line with first‐principles modelling. Under visible light irradiation, Co−CN reduces acetylene to ethylene with stable activity for over 40 days of continuous operation, ≥99.9% selectivity, and provides means for coupling organic upgrading to produce valuable oxidation products. The heterogeneous Co−CN can be easily recovered and reused repeatedly without loss of catalytic activity and structural integrity. Thereby, the integrated and recyclable platform overcomes the need of coupling a separate photosensitizer to a catalyst, and using noble metal catalysts with an external H ₂ gas feed.

Here, we report a [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) derivative functionalized with a β-sheet-forming peptide which alternates in its sequence Phe and Glu residues. The BTBT core is a popular structural motif in the design of high-mobility organic semiconductors. The insertion of the self-assembling subunit allows control of the supramolecular organization. This molecule self-assembles in water to give hydrogels over a broad range of pH values. Hydrogelation is triggered by both pH changes and variations in salt concentrations. Transmission electron microscopy shows the formation of long-range self-assembled 1D structures. The key role of hydrogen bonding and π–π interactions in hierarchical self-assembly is investigated using absorption, emission, infrared and circular dichroism spectroscopy. This is the first example of demonstrating the formation of supramolecular hydrogels containing the BTBT structure.

A Cu-loaded hydrogen-bonded organic framework enables visible-light-driven semi-hydrogenation of acetylene to ethylene in water, combining photosensitizer and catalyst in a single material to achieve ≥99.9% selectivity under mild conditions.