The present invention relates to electronic devices, especially electroluminescent devices, comprising azapyrenes of formula (I), or formula (III), wherein Y1, Y2, Y3, Y4, X1, X2 and X3 are independently each other N, or CR4, with the proviso that at least one of the groups X1, X2 and X3 is a group CR4, R1 is hydrogen, F, -SiR100R101R102, or an organic substituent, R4 is hydrogen, F, -SiR100R101R102, or an organic substituent, or any of the substituents R1, R1' and R4, which are adjacent to each other, together form an aromatic, or heteroaromatic ring, or ring system, which can optionally be substituted, m is an integer of 1 to 6, and R100, R101 and R102 are independently of each other a C1-C8alkyl group, a C6-C24aryl group, or a C7-C12aralkylgroup, which may optionally be substituted, and Q is a linking group; with the proviso that in the compound of formula (III) at least one of the substituents R1, or R4 is a group Q; especially as host for phosphorescent emitters, electron transporting materials, or emitter materials. The hosts may function with phosphorescent materials to provide improved efficiency, stability, manufacturability, or spectral characteristics of electroluminescent devices.