The key intermediate tetrachloropyrazine (4ClPz) was synthesized from dioxopiperazine and a mixture of POCl3 and PCl5 following a literature protocol. 4ClPz was then reacted with either carbazole (Cz), di-tert-butyl-9H-carbazole (tCz), or 5H-pyrido [3,2-b]indole (α-Cb) under SNAr conditions to obtain 4CzPz, 4tCzPz and 4αCbPz in moderate-to-good yields (Scheme 1). The three emitters were purified by silica gel chromatography followed by temperature gradient vacuum sublimation, and the purity was verified by elemental analysis (Figures ) and high-performance liquid chromatography (HPLC) analysis (Figures ). The three emitters were characterized using a combination of 1 H and 13 C NMR spectroscopy (Figures ), high-resolution mass spectrometry and melting point determination.