For a long time, phosphors with long‐lived emission are dominated by rare earth/transition metal ion‐doped sulfides and oxides. Recently, organic materials capable of emitting long‐lived room‐temperature phosphorescence (RTP) are reported, carbon skeletons are almost the exclusive structural feature of the conjugated luminophores. Herein, we reported that boric acid, a non‐metal and C‐free material, could emit RTP with lifetime up to 0.3 s. Detailed investigations indicated the weak conjugation between the n electrons of the O atoms in the B‐O confined space was the possible origin of RTP. Similar RTP was also found in electron‐rich N/F systems, namely, BN and BF3 (BF4−). Importantly, the vacant pz0 orbital of B was found to contribute to the relevant unoccupied molecular orbitals involved in excitation, which is different from previous reports on phosphorescence from arylboronic acids. The results confirm the unique role of B as a versatile structure motif for construction of new RTP materials.

Designing organic fluorescent and phosphorescent materials based on various core fluorophore has gained great attention, but it is unclear whether similar luminescent units exist for inorganic materials. Inspired by the BX6 octahedral structure of luminescent metal halide perovskites (MHP), here we propose that the BX6 octahedron may be a core structure for luminescent inorganic materials. In this regard, excitation-dependent color-tunable phosphorescence is discovered from α-AlF3 featuring AlF6 octahedron. Through further exploration of the BX6 unit by altering the dimension and changing the center metal (B) and ligand (X), luminescence from KAlF4, (NH4)3AlF6, AlCl3, Al(OH)3, Ga2O3, InCl3, and CdCl2 are also discovered. The phosphorescence of α-AlF3 can be ascribed to clusterization-triggered emission, i.e., weak through space interaction of the n electrons of F atoms bring close proximity in the AlF6 octahedra (inter/intra). These discoveries will deepen the understanding and contribute to further development of BX6 octahedron-based luminescent materials.

Unexpected color-tunable ultralong room-temperature phosphorescence (RTP, τ ~ 0.5 s) was observed from EDTA (and also EDTA salts, chelates, and structural analogues). Through both experimental and theoretical investigations, the through-space...

The impressive and unexpected long‐lived room‐temperature phosphorescence of boric acid (H3BO3) is unveiled by Peng Wu and co‐workers in their Research Article on page 9500. Unlike traditional metallic inorganic or aromatic organic phosphors, the phosphorescence originates from the weak conjugation of lone pair electrons from O atoms. The vacant pz orbital of B and the regular arrangement in the crystalline state with layer‐like packing through abundant hydrogen bonding are found to contribute to the long‐lived emission.