{Reference Type}: Journal Article {Title}: Organic thermally activated delayed fluorescence material with strained benzoguanidine donor. {Author}: Brannan AC;Beaumont EFP;Phuoc NL;Whitehead GFS;Linnolahti M;Romanov AS; {Journal}: Beilstein J Org Chem {Volume}: 19 {Issue}: 0 {Year}: 2023 {Factor}: 2.544 {DOI}: 10.3762/bjoc.19.95 {Abstract}: Organic thermally activated delayed fluorescence (TADF) materials have been widely investigated due to their impressive electronic properties and applied potential for the third generation of organic light-emitting diodes (OLED). We present organic TADF material (4BGIPN) based on the strained benzoguanidine donor and compare it with the benchmark carbazole-based material (4CzIPN). Extended π-conjugation in 4BGIPN material results in yellow-green luminescence at 512 nm with a fast radiative rate of 5.5 × 10-5 s-1 and a photoluminescence quantum yield of 46% in methylcyclohexane solution. Such a nitrogen-rich 4BGIPN material has a significantly stabilized highest occupied molecular orbital (HOMO) at -6.4 eV while the lowest unoccupied molecular orbital (LUMO) at -4.0 eV, indicating potential suitability for application as the electron transport layer or TADF class III emitter in OLEDs.