| abstract |
The present invention relates to compounds of formula (I), which are characterized in that they are substituted by benzimidazo[1,2-a]benzimidazo-5-yl and/or benzimidazo[1,2-a]benzimidazo-2,5- ylene groups and in that at least one of the substituents B1, B2, B3, B4, B5, B6, B7 and B8 represents N; a process for their production and their use in electronic devices, especially electroluminescent devices. When used as host material for phosphorescent emitters in electroluminescent devices, the compounds of formula (I) may provide improved efficiency, stability, manufacturability, or spectral characteristics of electroluminescent devices. |