Consecutive ( <i>Pseudo‐</i> )Four‐Component Synthesis of <i>Meta</i> ‐ and <i>Ortho</i> ‐Biaryl Triarylamines with Tunable Emission and Redox Properties

The strategic combination of Suzuki coupling and Buchwald–Hartwig amination in consecutive ( pseudo‐ )four‐component syntheses provides a highly efficient and modular route to meta ‐ and ortho ‐biaryl‐substituted triarylamines ( m ‐ and o ‐bTAA), thereby expanding a substance library that has previously focused on para ‐bTAA. The broad range of novel bTAA enables comprehensive investigations of their electronic properties and reveals highly tunable emission in solution from blue to yellow, with quantum yields up to 55%, and up to 26% in the solid state. The bTAA also show strong potential as stimulus‐responsive luminophores due to their pronounced positive emission solvatochromism, which indicates substantial charge transfer character—particularly in the m ‐bTAA—as well as aggregation‐induced emission in DMSO/water mixtures with with intensity enhancements of up to 75‐fold. Quantitative 2D Hammett correlations combined with quantum‐chemical calculations systematically rationalize substituent effects not only on the emission properties but also on the low, reversible redox potentials determined by cyclic voltammetry. Cyclic voltammetry further reveals irreversible dimerization processes in certain unsubstituted bTAA. In addition to para ‐substituents, the biaryl substitution pattern ( meta , ortho , or para ) also proves to be a finely tunable parameters, opening new opportunities for the rational design of tailored bTAA emitters with predictable structure–property relationships.