Used as a key building block in organic light-emitting diodes (OLEDs), particularly in blue-emitting materials due to its high thermal stability and good hole-transport properties. Its rigid spiro structure helps prevent close molecular packing, reducing aggregation and excimer formation, which enhances emission efficiency. Commonly employed in host materials for phosphorescent OLEDs (PhOLEDs) and thermally activated delayed fluorescence (TADF) devices. Also explored in perovskite solar cells as a hole-transport material owing to its suitable energy levels and film-forming characteristics.