Pyridinium molecules are developed as electron- and energy-transfer mediators to boost the activity of air oxygen and thus achieve highly efficient photocatalytic oxidation of alcohols without any noble metal and additional co-catalysts/additives under mild conditions.

Benefiting from the regulation of ROS species through a simple and feasible strategy, an efficient and switchable photocatalytic protocol for the chemoselective synthesis of aldehydes and carboxylic acids via oxidation of primary alcohols under mild conditions has been developed. Using the pyridinium derivative as a metal-free organic photocatalyst, a variety of benzyl alcohols can be converted into aldehydes or carboxylic acids under an air atmosphere at room temperature with high selectivity and yield via simple solvent regulation. A feasible tandem reaction combining the pyridinium-catalyzed alcohol-to-aldehyde conversion and catalyst-free photoinduced oxidation of aromatic aldehydes provides a powerful and efficient approach for the one-pot oxidation of benzyl alcohols to carboxylic acids, while a small amount of water can effectively regulate the competition of electron transfer and energy transfer and inhibit the generation of carboxylic acids, facilitating highly efficient and selective oxidation of alcohols to aldehydes.

Dual-photoresponsive coordination polymer displaying color-distinguishable radical states has been obtained based on the synergism of photocycloaddition and photoinduced electron transfer reactions.

Photomechanical motion triggered by [2 + 2] cycloaddition as well as simultaneous photochromic and fluorescence changes has been achieved by introducing flexible methylene groups and cation–π interactions into a pyridinium-based coordination complex.

Charge transfer complexes (CTCs) have become a promising and new class of the photothermal conversion material, in which the donor and acceptor can be regulated to control the energy gap,...