An efficient electrochemical method for benzylic C­(sp3)–H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)­methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.

Launching the intermolecular through‐space charge transfer (TSCT) from a bicomponent assembly for photophysical property manipulation is of great significance in fluorescence probe design. Here, we demonstrate the elaborate control of droplet evaporation dynamics for intermolecular TSCT can facilitate the ultrasensitive detection of JWH‐018, a representative synthetic cannabinoid. Driven by diverse intermolecular interactions, the probe, and JWH‐018 assemble in a closely stacked manner to emit strong fluorescence at 477 nm, ascribing to the intermolecular TSCT at the S2 state. The strategy realizes an ultra‐low limit of detection of 11 nmol/mL and great selectivity towards JWH‐018. The practicability is further verified by constructing a sensing chip for JWH‐018 aerosol detection, which facilitates the on‐site drug abuser screening with the naked eye. Moreover, the proposed assembly‐enabled TSCT is expected to find a variety of applications for optoelectronic materials design and photophysical mechanism‐dominated molecular recognition.