Luminescent materials containing multiple benzoxaphosphole units

A series of bisbenzoxaphospholes and a trisbenzoxaphosphole have been prepared and characterized. These extended p-conjugated heterocyclic phosphaalkenes display significant fluorescence in solution having quantum yields between 0.12 and 0.85. The solid state structure of a bisbenzoxaphosphole reveals evidence for extended conjugation, as do DFT calculations.