For oximetry applications, the first dual red–near-infrared (NIR) emissive organic light-emitting diode (OLED) based on mixed-ligand complexes Eu_xYb_1–x(dbm)₃BPhen (x = 0; 0.01; 0.02; 0.05; 0.1; 1) is obtained. The photoluminescence quantum yields of the ytterbium and europium in the obtained complexes reach 0.9 and 31%, respectively, which are rather high values for the complexes of these ions. Dual visible–NIR emissive compounds Eu_xYb_1–x(dbm)₃BPhen are tested in OLEDs, and Eu_0.05Yb_0.95(dbm)₃BPhen demonstrates the most intense electroluminescence both in visible (270 cd/m²) and NIR range (19 μW/cm²). The Eu_0.05Yb_0.95(dbm)₃BPhen-based OLED is successfully used to produce the first lanthanide OLED-based pulsimeter prototype.