A mixture of H₂dcbpy [B3502] (2 mmol, 0.5 g) and Ir₂(ppy)₄Cl₂ [D5744] (1 mmol, 1 g) is dissolved in CH₃OH (100 mL). Excessive Na₂CO₃ is added to the reaction mixture and then heated to reflux under stirring for 5 h. After cooling to room temperature, the solvent is removed under rotary evaporation. Deionized water is added to dissolve the precipitation by stirring, and the complex is achieved by the addition of hydrochloric acid, and then filtered and dried (82% yield based on Ir).