AbstractA critical step in advancing the practical application of copper‐based organic light‐emitting diodes (OLEDs) is to bridge the large gap between device efficiency and operational stability at practical luminance. Described is a panel of air‐ and thermally stable two‐coordinate Cu^I emitters featuring bulky pyrazine‐ (PzIPr) or pyridine‐fused N‐heterocyclic carbene (PyIPr*) and carbazole (Cz) ligands with enhanced amide‐Cu‐carbene bonding interactions. These Cu^I emitters display thermally activated delayed fluorescence (TADF) from the ¹LL′CT(Cz→PzIPr/PyIPr*) excited states across the blue to red regions with exceptional radiative rate constants of 1.1–2.2×10⁶ s⁻¹. Vapour‐deposited OLEDs based on these Cu^I emitters showed excellent external quantum efficiencies and luminance up to 23.6 % and 222 200 cd m⁻², respectively, alongside record device lifetimes (LT₉₀) up to 1300 h at 1000 cd m⁻² under our laboratory conditions, highlighting the practicality of the Cu^I‐TADF emitters.