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In this study, yellow thermally activated delayed fluorescence (TADF) emitter PTZ-SA has been designed and synthesized by incorporating phenothiazine as donor and benzothiadiazine-1,1-dioxide as an acceptor. The molecule is also screened for aggregation induced emission in THF/Water system. PTZ-SA shows exceptionally high glass transition temperature (T g ) of 188 °C which clearly highlights good thermal stability of the material. The energy gap (ΔE ST ) between singlet (S1) and triplet (T1) excitons is sufficiently small (0.08 eV) for the reverse intersystem crossing. Yellow electroluminescence peak is observed at 568 nm with Commission Internationale de L'Eclairage coordinates of (0.44, 0.50). The external quantum efficiency of 4.2 % from PTZ-SA is achieved in yellow emitting OLED with turn on voltage of 5.1 V. Moreover, sufficiently high triplet energy of 2.5 eV and good film forming ability of PTZ-SA, encouraged us to study its electro-phosphorescent properties. Nevertheless, the red phosphorescent OLED device incorporating PTZ-SA dopped with a red emitter Ir(piq) 2 acac exhibited maximum external quantum efficiency, power efficiency and luminescence efficiency of 8.1 %, 7.2 lm W À 1 and 5.1 cd A À 1 , respectively.