The synthesis of the three emitters is outlined in Scheme 1. The key intermediate, tetrachloropyrazine, (4ClPz) was synthesized in 40% yield from dioxopiperazine upon reaction with phosphorus pentachloride. 25 4ClPz was reacted with excess carbazole under SNAr conditions to obtain 4CzPyZ in a yield of 60%, which is significantly improved compared to the 2.5% previously reported using a Suzuki-Miyaura cross-coupling strategy. For the synthesis of 3CzBPz, 4ClPz was converted to the biphenylsubstituted intermediate (3ClBPz) via a Suzuki-Miyaura reaction, which was then reacted with carbazole to obtain 3CzBPz in a 70% yield. For the synthesis of 2CzBPz, 4ClPz was reacted first with carbazole to obtain the dicarbazole intermediate 2Cz2ClPz, which was then directly reacted with 2-biphenylboronic acid via a Suzuki-Miyaura cross-coupling reaction to obtain 2Cz2BPz in a yield of 65%. The three emitters were characterized by combination of 1 H and 13 C NMR spectroscopy, X-ray diffraction (XRD), high-resolution mass spectrometry, melting point determination, high performance liquid chromatography (HPLC), and elemental analysis. 43.45°, the other of 55.09° and 56.73°. For 3CzBPz, the carbazole at the ortho position to the biphenyl is twisted with a dihedral angle of 47.39°, while the dihedral angles for the carbazoles at the meta and para positions are larger at 56.01° and 52.71°, respectively. The dihedral angle between the carbazoles and the pyrazine in 2CzBPz are at the higher end of the range seen, at 55.06°, rather different to those of a previously reported green-emissive pyrazine-containing TADF emitter pDTCz-DPzS [38.20(8)°]. As was the case for the previously reported structure of the DMF solvate of 4CzPyz,