A compound, wherein the compound is selected from the group comprising formula 1, G1 to G6, G12 and G49: wherein X is O or S; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 are independently selected from H, phenyl, naphthyl, or biphenyl; m is 0; n is 0; Y is N or CH, preferably N; Ar 1 is selected from phenyl, naphthyl, biphenyl, phenanthryl triphenyl, or anthryl group; Ar 2 is selected from divalent phenyl, naphthyl, biphenyl, phenanthryl, triphenyl, or anthryl group; Ar 3 is selected from H, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl selected from a group consisting of pyridine, pyrimidine, triazine, quinoline, quinoxaline, benzo acridine, dibenzo acridine, phenanthroline, carbazole, dibenzofurane, dibenzothiophene, the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2 with R' being alkyl, aryl or heteroaryl, D, F or CN, C 1 to C 16 alkyl, partially or perfluorinated C 1 to C 16 alkyl, partially or perdeuterated 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 4 is selected from H, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl selected from a group consisting of pyridine, quinoline, quinoxaline, phenanthroline, carbazole, dibenzofurane, dibenzothiophene, the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2 with R' being alkyl, aryl or heteroaryl, D, F or CN, C 1 to C 16 alkyl, partially or perfluorinated C 1 to C 16 alkyl, partially or perdeuterated 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 alkyl includes C 1 to C 16 alkyl, C 3 to C 16 branched alkyl and C 3 to C 16 cyclic alkyl. X is O or S; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 are independently selected from H, phenyl, naphthyl, or biphenyl; m is 0; n is 0; Y is N or CH, preferably N; Ar 1 is selected from phenyl, naphthyl, biphenyl, phenanthryl triphenyl, or anthryl group; Ar 2 is selected from divalent phenyl, naphthyl, biphenyl, phenanthryl, triphenyl, or anthryl group; Ar 3 is selected from H, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl selected from a group consisting of pyridine, pyrimidine, triazine, quinoline, quinoxaline, benzo acridine, dibenzo acridine, phenanthroline, carbazole, dibenzofurane, dibenzothiophene, the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2 with R' being alkyl, aryl or heteroaryl, D, F or CN, C 1 to C 16 alkyl, partially or perfluorinated C 1 to C 16 alkyl, partially or perdeuterated 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 4 is selected from H, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl selected from a group consisting of pyridine, quinoline, quinoxaline, phenanthroline, carbazole, dibenzofurane, dibenzothiophene, the substituents are selected from C 6 to C 18 aryl, C 3 to C 25 heteroaryl, -PO(R') 2 with R' being alkyl, aryl or heteroaryl, D, F or CN, C 1 to C 16 alkyl, partially or perfluorinated C 1 to C 16 alkyl, partially or perdeuterated 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. <EOS>