Palladium-catalyzed cross-coupling reactions are one of the most powerful and versatile methods to synthesize a wide range of complex functionalized molecules. However, the development of solid-state cross-coupling reactions remains extremely limited. Here, we report a rational strategy that provides a general entry to palladium-catalyzed Buchwald-Hartwig cross-coupling reactions in the solid state. The key finding of this study is that olefin additives can act as efficient molecular dispersants for the palladium-based catalyst in solid-state media to facilitate the challenging solid-state cross-coupling. Beyond the immediate utility of this protocol, our strategy could inspire the development of industrially attractive solvent-free palladium-catalyzed cross-coupling processes for other valuable synthetic targets.

Semiconductor nanomaterials with efficient polarized‐light control in the blue region of the visible spectrum are promising candidates for modern and future photo‐information technology, display devices, and optical sensing applications. New‐type semiconductor Eu(OCN)2 nanocrystals with circularly polarized absorption (CD: circular dichroism) and emission (CPL: circularly polarized luminescence) under an applied magnetic field are demonstrated here for the first time. The effective CD signal at 1.6 T was observed at approximately 440 nm. The dissymmetry factor of CPL under 100 K, gM‐CPL, was estimated to be 0.01. These characteristic circularly polarized absorption and emission phenomena of Eu(OCN)2 nanocrystals should be caused by combination between the “Faraday A and C terms” of the magnetic moment in the excited state. Polarized‐light control using Eu(OCN)2 nanocrystals in the blue‐light region of the electromagnetic spectrum is a large first step into a new world of photo‐functional semiconductor nanomaterials.

The Cover Feature shows that the magnetic semiconductor Eu‐OCN provides polarized luminescence for photoscience and technology. More information can be found in the Communication by Yasuchika Hasegawa and co‐workers.