New indole–carbazole hybrids as glass-forming high-triplet-energy materials

New indole–carbazole hybrids are reported as glass-forming high-triplet-energy materials. They were synthesized by the tandem addition–elimination–(Michael) addition reaction of 9-ethyl-9H-carbazole-3-carbaldehyde with 1H-indole or 2-phenyl-1H-indole followed by alkylation with the different agents. The synthesized compounds exhibit moderate thermal stabilities with 5% weight loss temperatures ranging from 281 to 308 °C. Their glass transition temperatures are in the range of 89–143 °C. Most of the new indole–carbazole hybrids in dilute solutions exhibit high triplet energies (2.97–2.99 eV).