Efficient deep-blue-emitting tetradentate platinum complexes with a narrow spectral bandwidth are presented, which demonstrate CIEx approximate to 0.15 and CIE gamma < 0.1. Ultimately, an organic light-emitting diode (OLED) with 24.8% peak external quantum efficiency and CIE coordinates of (0.147, 0.079) is fabricated using PtON7-dtb.