Compound of the Formula wherein Ar 4 is a group having the Formula wherein the asterisk symbol "*" in Formula represents the position of binding of the group having the Formula; L is selected from substituted or unsubstituted C 6 to C 18 arylene; Ar 1 is selected from substituted or unsubstituted C 3 to C 24 heteroaryl, wherein the heteroaryl comprises at least two N-atoms; Ar 2 and Ar 3 are independently selected from substituted or unsubstituted C 6 to C 24 aryl and/or substituted or unsubstituted C 4 to C 24 heteroaryl but the selected group cannot be the same for Ar 2 and Ar 3, R 1 to R 10 are independently selected from the group consisting of H, D, F, C 1 to C 20 alkyl, C 6 to C 20 aryl, C 2 to C 20 heteroaryl and a group having the Formula; and R 1 and R 2; or R 2 and R 3; or R 3 and R 4; or R 5 and R 6 may independently from each other form a fused ring or a system of fused rings; wherein, in the respective substituted groups, the substituents each are independently selected from the group consisting of D, F, C 1 to C 20 linear alkyl, C 3 to C 20 branched alkyl, C 3 to C 20 cyclic alkyl, C 1 to C 20 linear alkoxy, C 3 to C 20 branched alkoxy, C 1 to C 12 linear fluorinated alkyl, C 1 to C 12 linear fluorinated alkoxy, C 3 to C 12 branched fluorinated cyclic alkyl, C 3 to C 20 fluorinated cyclic alkyl, C 3 to C 12 fluorinated cyclic alkoxy, CN, RCN, C 6 to C 20 aryl, C 2 to C 20 heteroaryl, OR, SR, (C=O)R, (C=O)NR 2, SiR 3, (S=O)R, (S=O) 2 R, (P=O)R 2; wherein each R is independently selected from the group consisting of C 1 to C 20 linear alkyl, C 1 to C 20 alkoxy, C 1 to C 20 thioalkyl, C 3 to C 20 branched alkyl, C 3 to C 20 cyclic alkyl, C 3 to C 20 branched alkoxy, C 3 to C 20 cyclic alkoxy, C 3 to C 20 branched thioalkyl, C 3 to C 20 cyclic thioalkyl, C 6 to C 20 aryl and C 2 to C 20 heteroaryl, wherein alkyl encompasses linear as well as branched and cyclic alkyl; wherein aryl is selected from phenyl, fused aromatics such as naphthalene, anthracene, phenanthracene or tetracene, and furthermore biphenyl, oligo-or polyphenyls and further aromatic hydrocarbon substituents such as fluorenyl; and wherein compounds of formula A-W wherein A is selected from the group of formula (VIa) or (VIb) and W is selected from are excluded. wherein Ar 4 is a group having the Formula wherein the asterisk symbol "*" in Formula represents the position of binding of the group having the Formula; L is selected from substituted or unsubstituted C 6 to C 18 arylene; Ar 1 is selected from substituted or unsubstituted C 3 to C 24 heteroaryl, wherein the heteroaryl comprises at least two N-atoms; Ar 2 and Ar 3 are independently selected from substituted or unsubstituted C 6 to C 24 aryl and/or substituted or unsubstituted C 4 to C 24 heteroaryl but the selected group cannot be the same for Ar 2 and Ar 3, R 1 to R 10 are independently selected from the group consisting of H, D, F, C 1 to C 20 alkyl, C 6 to C 20 aryl, C 2 to C 20 heteroaryl and a group having the Formula; and R 1 and R 2; or R 2 and R 3; or R 3 and R 4; or R 5 and R 6 may independently from each other form a fused ring or a system of fused rings; wherein, in the respective substituted groups, the substituents each are independently selected from the group consisting of D, F, C 1 to C 20 linear alkyl, C 3 to C 20 branched alkyl, C 3 to C 20 cyclic alkyl, C 1 to C 20 linear alkoxy, C 3 to C 20 branched alkoxy, C 1 to C 12 linear fluorinated alkyl, C 1 to C 12 linear fluorinated alkoxy, C 3 to C 12 branched fluorinated cyclic alkyl, C 3 to C 20 fluorinated cyclic alkyl, C 3 to C 12 fluorinated cyclic alkoxy, CN, RCN, C 6 to C 20 aryl, C 2 to C 20 heteroaryl, OR, SR, (C=O)R, (C=O)NR 2, SiR 3, (S=O)R, (S=O) 2 R, (P=O)R 2; wherein each R is independently selected from the group consisting of C 1 to C 20 linear alkyl, C 1 to C 20 alkoxy, C 1 to C 20 thioalkyl, C 3 to C 20 branched alkyl, C 3 to C 20 cyclic alkyl, C 3 to C 20 branched alkoxy, C 3 to C 20 cyclic alkoxy, C 3 to C 20 branched thioalkyl, C 3 to C 20 cyclic thioalkyl, C 6 to C 20 aryl and C 2 to C 20 heteroaryl, wherein alkyl encompasses linear as well as branched and cyclic alkyl; wherein aryl is selected from phenyl, fused aromatics such as naphthalene, anthracene, phenanthracene or tetracene, and furthermore biphenyl, oligo-or polyphenyls and further aromatic hydrocarbon substituents such as fluorenyl; and wherein compounds of formula A-W wherein A is selected from the group of formula (VIa) or (VIb) and W is selected from are excluded.