We synthesized and evaluated new deep blue fluorescence emitter, KH-FBD1. This emitter exhibits pure deep blue PL spectrum peak at 452 nm with 20 nm full width half maximum. Fabricated device shows high efficiency of 7.4% with deep blue color coordinate of (0.14, 0.07). In addition, this device indicates long operational lifetime (LT₉₅) of 100 hours at initial luminance 1,000 cd/m². It also shows high efficiency of 12.7% in high T₁ device with maintaining the deep blue color characteristic.