Phenothiazinyl Boranes: A New Class of AIE Luminogens with Mega Stokes Shift, Mechanochromism, and Mechanoluminescence

Phenothiazines with a dimesityl boron moiety, a new class of aminoboranes with B−N linkage, were synthesized. These aminoboranes exhibited interesting photophysical behavior including aggregation-induced emission (AIE), mechanochromism (MC), mechanoluminescence (ML), and a mega Stokes shift (up to 312 nm in hexane). The solid-state emission of the aminoboranes could be switched reversibly by grinding–fuming processes. Furthermore, the phenothiazine derivative with a bromo and an arylborane group at 3- and 7-positions exhibited bright mechanoluminescence.