Advances in the design of functionalized 1,4-diazines as components for photo- or/and electroactive materials

Pyrazines and quinoxalines represent a well-known class of electron-deficient heterocyclic compounds, which are exploited as electron-withdrawing fragments in push-pull structures for intramolecular charge transfer (ICT). The considerable interest in pyrazine and quinoxaline-based chromophores is due to their wide range of applications in various fields; they can be used as fluorescent sensors (to determine polarity, pH, metal cations, or to detect explosives), as dyes for microscopy and diagnostic in medicine, for lighting in organic light-emitting devices (OLEDs) and NLO materials. This review deals with the data on synthetic approaches to (hetero)aryl-substituted, annelated 1,4-diazines, as well as quinoxaline-based polymers reported over the past 10 years. Also, their applications related to photoluminescence, electroluminescence, thermally activated delayed fluorescence, and nonlinear optical and sensory properties are supposed to be considered.