An aromatic monomer compound of formula I-X: wherein X independently from each other, are Br or I; R a independently of each other are hydrogen or linear or branched or cyclic C 1 -C 30 alkyl, preferably hydrogen or methyl; R b independently of each other, are hydrogen; linear or branched or cyclic C 1 -C 30 alkyl which is unsubstituted or substituted by one or more OH, C 1 -C 4 alkoxy, phenyl, or by CN; C 2 -C 12 alkyl which is interrupted by one or more non-consecutive O; halogen; OH; OR 3; SR 3; CN; NO 2; NR 1 R 2; R 3; OR 3; O OR 3; O NR 1 R 2; O R 3; C 1 -C 12 alkoxy; C 1 -C 12 alkylthio; (C 1 -C 6 alkyl)-NR 7 R 8; or-O-(C 1 -C 6 alkyl)NR 1 R 2; aryl or heteroaryl; wherein aryl is preferably phenyl, biphenyl, naphthyl, or anthryl all of which are unsubstituted or are substituted by one or more C 1 -C 4 -alkyl, CN, OR 3, SR 3, CH 2 OR 3, OR 3, NR 1 R 2 or halogen; R c independently of each other, are hydrogen; linear or branched or cyclic C 1 -C 30 alkyl which is unsubstituted or substituted by one or more OH, C 1 -C 4 alkoxy, phenyl, or by CN; C 2 -C 12 alkyl which is interrupted by one or more non-consecutive O; halogen; OH; OR 3; SR 3; CN; NO 2; NR 1 R 2; R 3; OR 3; O OR 3; O NR 1 R 2; O R 3; C 1 -C 12 alkoxy; C 1 -C 12 alkylthio; (C 1 -C 6 alkyl)-NR 7 R 8; or-O-(C 1 -C 6 alkyl)NR 1 R 2; or two groups R a, R b and R c, may together with the carbon atoms they are attached to, form a 5-8-membered cycle or heterocycle; R 1 and R 2 are, independently of each other, hydrogen, linear or branched C 1 -C 6 alkyl or phenyl, or R 1 and R 2 together with the nitrogen atom to which they are bonded form a group selected from R 3 is selected from H, C 1 -C 30 alkyl and phenyl, which may be unsubstituted or substituted by one or more C 1 -C 4 alkyl, phenyl, halogen, C 1 -C 4 alkoxy or C 1 -C 4 alkylthio. X independently from each other, are Br or I; R a independently of each other are hydrogen or linear or branched or cyclic C 1 -C 30 alkyl, preferably hydrogen or methyl; R b independently of each other, are hydrogen; linear or branched or cyclic C 1 -C 30 alkyl which is unsubstituted or substituted by one or more OH, C 1 -C 4 alkoxy, phenyl, or by CN; C 2 -C 12 alkyl which is interrupted by one or more non-consecutive O; halogen; OH; OR 3; SR 3; CN; NO 2; NR 1 R 2; R 3; OR 3; O OR 3; O NR 1 R 2; O R 3; C 1 -C 12 alkoxy; C 1 -C 12 alkylthio; (C 1 -C 6 alkyl)-NR 7 R 8; or-O-(C 1 -C 6 alkyl)NR 1 R 2; aryl or heteroaryl; wherein aryl is preferably phenyl, biphenyl, naphthyl, or anthryl all of which are unsubstituted or are substituted by one or more C 1 -C 4 -alkyl, CN, OR 3, SR 3, CH 2 OR 3, OR 3, NR 1 R 2 or halogen; R c independently of each other, are hydrogen; linear or branched or cyclic C 1 -C 30 alkyl which is unsubstituted or substituted by one or more OH, C 1 -C 4 alkoxy, phenyl, or by CN; C 2 -C 12 alkyl which is interrupted by one or more non-consecutive O; halogen; OH; OR 3; SR 3; CN; NO 2; NR 1 R 2; R 3; OR 3; O OR 3; O NR 1 R 2; O R 3; C 1 -C 12 alkoxy; C 1 -C 12 alkylthio; (C 1 -C 6 alkyl)-NR 7 R 8; or-O-(C 1 -C 6 alkyl)NR 1 R 2; or two groups R a, R b and R c, may together with the carbon atoms they are attached to, form a 5-8-membered cycle or heterocycle; R 1 and R 2 are, independently of each other, hydrogen, linear or branched C 1 -C 6 alkyl or phenyl, or R 1 and R 2 together with the nitrogen atom to which they are bonded form a group selected from R 3 is selected from H, C 1 -C 30 alkyl and phenyl, which may be unsubstituted or substituted by one or more C 1 -C 4 alkyl, phenyl, halogen, C 1 -C 4 alkoxy or C 1 -C 4 alkylthio. R 3 is selected from H, C 1 -C 30 alkyl and phenyl, which may be unsubstituted or substituted by one or more C 1 -C 4 alkyl, phenyl, halogen, C 1 -C 4 alkoxy or C 1 -C 4 alkylthio.