Synthesis and Photophysical Properties of Tetra-Aryl-Substituted 2H-benzo[d][1,2,3]triazole Derivatives with...

Dual-state emission (DSE) molecules, which fluoresce efficiently both in dilute solution and aggregated state, bridge the limitations of aggregation induced emission (AIE) and aggregation caused quenching (ACQ) systems and therefore hold exceptional promise for next-generation luminescent materials. In this study, a series of new fluorescent compounds (1-4) based on 2H-benzo[d][1,2,3]triazole were designed and synthesized, and their photophysical properties were systematically investigated across different states. All four compounds exhibit 100% quantum yields (QY) in toluene and retain QY ≥ 44% in the powder state; notably, compounds 1 and 4 preserve QY above 60% in powder state, unambiguously confirming their DSE characteristics. Moreover, the emission profiles remain highly consistent regardless of solvent or aggregation state. In particular, compound 3 displays CIE₁₉₃₁ chromaticity coordinates of (0.15, 0.07) in all states, approaching the standard blue of (0.14, 0.08). Additionally, reversible mechanochromism was observed for compounds 2 and 4.