Electronic device

A compound of a formula (I-1-3)

• which may be substituted on the benzene rings at the positions shown as unsubstituted by R2 radicals, and where:
• both of the two Ar1 are selected, differently, from the formulae Ar1-59 to Ar1-62,
• each of which is substituted by R1 radicals;
• X is O or S;
• R1 is the same or different at each instance and is selected from H, N (R3)2;
• R2 H;
• R3 is the same or different at each instance and is selected from H, F, CN, straight-chain alkyl groups having 1 to 20 carbon atoms, and branched or cyclic alkyl groups having 3 to 20 carbon atoms, where the alkyl groups mentioned may each be substituted by one or more R4 radicals;
• R4 is the same or different at each instance and is selected from H, D, F, and CN;
• k is 0.