A compound according to formula 1: wherein R 1, R 2, R 3 and R 4 are independently selected from hydrogen, substituted or unsubstituted C 6 to C 38 aryl, substituted or unsubstituted C 3 to C 36 heteroaryl or C 1 to C 16 alkyl group, -PO(R') 2, D, F, CN, or formula 2; wherein the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2, D, F or CN, partially or perfluorinated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, partially or perfluorinated C 1 to C 16 alkoxy, partially or perdeuterated C 1 to C 16 alkoxy; R' is independently selected from alkyl, aryl or heteroaryl; a, b, c, d and e are independently 0, 1 or 2, wherein at least one of a, b, c or d is 1 or 2; wherein at least one of R 1, R 2, R 3 or R 4 is formula 2 Ar 1 is selected from substituted or unsubstituted C 6 to C 38 arylene, substituted or unsubstituted C 3 to C 36 heteroarylene or C 1 to C 16 alkylene group, wherein the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2, D, F or CN, partially or perfluorinated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, partially or perfluorinated C 1 to C 16 alkoxy, partially or perdeuterated C 1 to C 16 alkoxy; Ar 2 is selected from substituted or unsubstituted C 6 to C 38 aryl, substituted or unsubstituted C 3 to C 36 heteroaryl or C 1 to C 16 alkyl group, wherein the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2, D, F or CN, partially or perfluorinated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, partially or perfluorinated C 1 to C 16 alkoxy, partially or perdeuterated C 1 to C 16 alkoxy; wherein Ar 1 does not contain one or more CN substituents when Ar 2 is substituted or unsubstituted C 6 to C 38 aryl; wherein the following compound 3 is excluded: R 1, R 2, R 3 and R 4 are independently selected from hydrogen, substituted or unsubstituted C 6 to C 38 aryl, substituted or unsubstituted C 3 to C 36 heteroaryl or C 1 to C 16 alkyl group, -PO(R') 2, D, F, CN, or formula 2; wherein the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2, D, F or CN, partially or perfluorinated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, partially or perfluorinated C 1 to C 16 alkoxy, partially or perdeuterated C 1 to C 16 alkoxy; R' is independently selected from alkyl, aryl or heteroaryl; a, b, c, d and e are independently 0, 1 or 2, wherein at least one of a, b, c or d is 1 or 2; Ar 1 is selected from substituted or unsubstituted C 6 to C 38 arylene, substituted or unsubstituted C 3 to C 36 heteroarylene or C 1 to C 16 alkylene group, wherein the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2, D, F or CN, partially or perfluorinated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, partially or perfluorinated C 1 to C 16 alkoxy, partially or perdeuterated C 1 to C 16 alkoxy; Ar 2 is selected from substituted or unsubstituted C 6 to C 38 aryl, substituted or unsubstituted C 3 to C 36 heteroaryl or C 1 to C 16 alkyl group, wherein the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2, D, F or CN, partially or perfluorinated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, partially or perfluorinated C 1 to C 16 alkoxy, partially or perdeuterated C 1 to C 16 alkoxy; wherein Ar 1 does not contain one or more CN substituents when Ar 2 is substituted or unsubstituted C 6 to C 38 aryl; wherein the following compound 3 is excluded: Ar 2 is selected from substituted or unsubstituted C 6 to C 38 aryl, substituted or unsubstituted C 3 to C 36 heteroaryl or C 1 to C 16 alkyl group, wherein the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2, D, F or CN, partially or perfluorinated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, partially or perfluorinated C 1 to C 16 alkoxy, partially or perdeuterated C 1 to C 16 alkoxy; Ar 1 does not contain one or more CN substituents when Ar 2 is substituted or unsubstituted C 6 to C 38 aryl; wherein the following compound 3 is excluded: