A Polycyclic Aromatic Hydrocarbon Copolymer (PAHC) comprising a mixture of at least one heteroacene monomer unit having the Formula and at least one monomer unit having the Formula, further comprising one or more monomers,, (D'), and/or; wherein monomers of Formula can be the pure cis isomer, or the pure trans isomer, or a mixture of the cis and trans isomers; wherein Y 1 =Y 2 = S and R 1, R 4, R 8 and R 11 are independently selected from the group consisting of H, C 1 -C 6 alkyl and C 1 -C 6 alkoxy; wherein, R 2, R 3, R 9 and R 10 are independently selected from the group consisting of H, C 1 -C 6 alkyl and C 1 -C 6 alkoxy, provided that at least one of each pair of R 2 /R 3 and R 9 /R 10 are a bond, represented by -*, to another monomer unit having the Formula,,,, (D'), or; and wherein R 25, R 26 and R 27 are independently selected from the group consisting of C 1 -C 6 alkyl and C 2 -C 6 alkenyl, preferably independently selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, 1-propenyl and 2-propenyl, more preferably ethyl, n-propyl and isopropyl; wherein Ar 1, Ar 2 and Ar 3, which may be the same or different, each represent, independently if in different repeat units, an optionally substituted C 6-40 aromatic group (mononuclear or polynuclear), wherein preferably at least one of Ar 1, Ar 2 and Ar 3 is substituted with at least one or more polar group, and -* represents a bond to another monomer unit having the Formula,,,, (D'), or; wherein each R 1', R 2', R 3', R 4', R 5', R 6' and R 7', each of which may be the same or different, independently represents hydrogen; a branched or unbranched, substituted or unsubstituted C 1 -C 40 alkyl group; a branched or unbranched, substituted or unsubstituted C 2 -C 40 alkenyl group; a branched or unbranched, substituted or unsubstituted C 2 -C 40 alkynyl group; an optionally substituted C 3 -C 40 cycloalkyl group; an optionally substituted C 6 -C 40 aryl group; an optionally substituted C 1 -C 40 heterocyclic group; an optionally substituted C 1 -C 40 heteroaryl group; an optionally substituted C 1 -C 40 alkoxy group; an optionally substituted C 6 -C 40 aryloxy group; an optionally substituted C 7 -C 40 alkylaryloxy group; an optionally substituted C 2 -C 40 alkoxycarbonyl group; an optionally substituted C 7 -C 40 aryloxycarbonyl group; a cyano group (-CN); a carbamoyl group (-C(=O)NR 15 R 16); a carbonyl group (-C(=O)-R 17); a carboxyl group (-CO 2 R 18) a cyanate group (-OCN); an isocyano group (-NC); an isocyanate group (-NCO); a thiocyanate group (-SCN) or a thioisocyanate group (-NCS); an optionally substituted amino group; a hydroxy group; a nitro group; a CF 3 group; a halo group (Cl, Br, F, I); -SR 19; -SO 3 H; -SO 2 R 20; -SF 5; an optionally substituted silyl group; a C 2 -C 10 alkynyl group substituted with a - SH 2 R 22 group, a C 2 -C 10 alkynyl substituted with a -SiHR 22 R 23 group, or a C 2 -C 10 alkynyl moiety substituted with a -Si(R 22) x (R 23) y (R 24) z group; wherein each R 22 group is independently selected from the group consisting of a branched or unbranched, substituted or unsubstituted C 1 -C 10 alkyl group, a branched or unbranched, substituted or unsubstituted C 2 -C 10 alkynyl group, a substituted or unsubstituted C 2 -C 20 cycloalkyl group, a substituted or unsubstituted C 2 -C 10 alkenyl group, and a substituted or unsubstituted C 6 -C 20 cycloalkylalkylene group; each R 23 group is independently selected from the group consisting of a branched or unbranched, substituted or unsubstituted C 1 -C 10 alkyl group, a branched or unbranched, substituted or unsubstituted C 2 -C 10 alkynyl group, a substituted or unsubstituted C 2 -C 10 alkenyl group, a substituted or unsubstituted C 2 -C 20 cycloalkyl group, and a substituted or unsubstituted C 6 -C 20 cycloalkylalkylene group; R 24 is independently selected from the group consisting of hydrogen, a branched or unbranched, substituted or unsubstituted C 2 -C 10 alkynyl group, a substituted or unsubstituted C 2 -C 20 cycloalkyl group, a substituted or unsubstituted C 6 -C 20 cycloalkylalkylene group, a substituted C 5 -C 20 aryl group, a substituted or unsubstituted C 6 -C 20 arylalkylene group, an acetyl group, a substituted or unsubstituted C 3 -C 20 heterocyclic ring comprising at least one of O,N,S and Se in the ring; wherein x= 1 or 2; y=1 or 2; z=0 or 1; and (x+y+z)=3; wherein each of R 15, R 16, R 18, R 19 and R 20 independently represent H or optionally substituted C 1 -C 40 carbyl or hydrocarbyl group optionally comprising one or more heteroatoms; wherein R 17 represents a halogen atom, H or optionally substituted C 1 -C 40 carbyl or C 1 -C 40 hydrocarbyl group optionally comprising one or more heteroatoms; wherein n' = 1 to 3; wherein the PAHC is a random copolymer; and wherein monomer is present in an amount of at least 20 wt. %; monomer is present in an amount of at least 60 wt. % and the remainder is comprised of monomers,, (D') and/or, based on the total weight of all monomer units in the copolymer.