An acridine compound of formula (I), with a ring system K1 and K2: wherein n is 0, 1 or 2; A 1 and A 2 are independently selected from H or aromatic cyclic ring of unsubstituted or substituted phenylene, and the substituents are selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy, and at least one aromatic cyclic ring of A 1 and/or A 2 are annelated with the ring system K2 or the ring system K1; A 3 has the formula (Ia), having a ring system L1, or has the formula (Ib), having a ring system L2, or has the formula (Id), or has the formula (Ie), or has the formula (If): R 1 , R 2 are independently selected from unsubstituted or substituted C 6 to C 24 aryl and C 1 to C 18 alkyl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; R 3 is selected from unsubstituted or substituted C 6 to C 24 aryl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; R 4 , R 5 , R 6 and R 7 are independently selected from H, unsubstituted or substituted C 6 to C 24 aryl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; A 4 to A 12 are independently selected from unsubstituted or substituted C 6 to C 24 aryl and unsubstituted or substituted pyridyl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; wherein at least one of A 5 and/or A 6 are annelated with the ring system L1; wherein at least one of A 7 and/or A 8 and/or A 9 annelated with the ring system L2; and wherein formulas (Ia) to (If) of A 3 are connected at the position marked with "*" via a single bond. n is 0, 1 or 2; A 1 and A 2 are independently selected from H or aromatic cyclic ring of unsubstituted or substituted phenylene, and the substituents are selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy, and at least one aromatic cyclic ring of A 1 and/or A 2 are annelated with the ring system K2 or the ring system K1; A 3 has the formula (Ia), having a ring system L1, or has the formula (Ib), having a ring system L2, or has the formula (Id), or has the formula (Ie), or has the formula (If): R 1 , R 2 are independently selected from unsubstituted or substituted C 6 to C 24 aryl and C 1 to C 18 alkyl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; R 3 is selected from unsubstituted or substituted C 6 to C 24 aryl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; R 4 , R 5 , R 6 and R 7 are independently selected from H, unsubstituted or substituted C 6 to C 24 aryl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; A 4 to A 12 are independently selected from unsubstituted or substituted C 6 to C 24 aryl and unsubstituted or substituted pyridyl, and the substituents are independently selected from H, C 1 to C 18 alkyl and C 1 to C 18 alkoxy; wherein at least one of A 5 and/or A 6 are annelated with the ring system L1; wherein at least one of A 7 and/or A 8 and/or A 9 annelated with the ring system L2; and wherein formulas (Ia) to (If) of A 3 are connected at the position marked with "*" via a single bond. <EOS>