Despite significant progress in OLED technologies, the development of stable and color-pure blue phosphorescent emitters remains a major challenge. This study presents a newly designed tetradentate Pt(II) complex, 2024 Pt4, for blue phosphorescent OLED applications. The complex exhibits blue emission with maxima at 458 nm at room temperature and 448 nm at 77 K, indicating a relatively rigid excited-state structure. 2024 Pt4 shows a broader emission bandwidth (FWHM = 41 nm), implying enhanced vibronic coupling or residual intermolecular interactions. Electrochemical analysis reveals HOMO/LUMO energy levels of −5.2/−2.3 eV, suitable for OLED integration. In addition, a high decomposition temperature (Td = 388 °C) demonstrates excellent thermal robustness. These results provide insights into the structure–property relationship of tetradentate Pt(II) emitters and design considerations for improving color purity in deep-blue OLED materials.