Organoboron luminophores with extremely strong dual–phase emissions

Developing efficient dual–phase emission emitters upon organoboron luminophores remains a formidable challenge due to the ubiquitous self–absorption and deleterious π-π interactions from aromatic structure. Here, a new family of benzothiazole–enolate–based organoboron luminophores (HN1–4) with effective dual–phase emission was constructed. HN4 showed almost the highest quantum yield (QY) among this type of compound so far. The three-ring–fused rigid skeleton and moderate intramolecular charge transfer (ICT) effect ensured that HN4 could give rise to extremely strong emission in any solution (QY up to 99%). X-ray crystallographic analysis showed that the twisted core structure constructed by the boronic coordination of two penta-fluorobenzene of HN4 was responsible for intense emission in the solid state (QY up to 68%). Besides, HN4 exhibited a unique response to mechanical force accompanied by a reversible change of the QY. We believe that this strategy provides beneficial inspiration and methodology to design materials with high emissive quantum yield that can be used in a variety of luminescent events.