Used as a high-performance hole-transport material in organic light-emitting diodes (OLEDs), especially in blue phosphorescent and thermally activated delayed fluorescence (TADF) devices. Its spirobifluorene core with multiple p-tolyl groups provides excellent thermal stability, high glass transition temperature, and good film-forming properties. The compound facilitates efficient hole injection and transport while maintaining low driving voltages and high device efficiency. It is also employed in perovskite solar cells to improve device stability and charge transport. Its steric bulk helps suppress intermolecular interactions, reducing exciton quenching and enhancing luminescence efficiency.