1,4-Diazatriphenylene and Its Hetero-Fused Analogs: Synthesis and Applications

This review highlights the recent advances in the synthesis of 1,4-diazatriphenylenes and their various structural analogs. It focuses on several methodologies, including condensation reactions and intramolecular cyclizations of 2,3-di(het)aryl-substituted pyrazine derivatives. These methods exploit either oxidative photocyclization (the Mallory reaction), intramolecular cyclodehydrogenation (the Scholl reaction), or intramolecular SNH reactions (nucleophilic aromatic substitution of hydrogen) involving 2-bis(het)aryl-substituted 1,4-diazine derivatives. Additionally, the review explores the potential applications of these compounds as fluorescent and/or semiconducting materials in organic electronics, as well as their role in coordination chemistry and biological issues. It summarizes the literature from 2018 to March 2026, complementing the data discussed in our previous review.