NOVELTY - Polymer comprising 2,7-dithia-1,3,6,8-tetraaza-dicyclopenta(a,f)naphthalene repeating unit (I) is new, where the polymer has a degree of polymerization (n) of 3-1000.    USE - The polymer is useful in electronic device, an optical device, or an optoelectronic device comprising a thin film semiconductor, field effect transistor device, photovoltaic device, an organic light emitting device (all claimed), and photodetectors, where the optoelectronic device includes thin film semiconductors, the field effect transistor includes thin film transistors, and the organic light emitting device includes organic light emitting diodes, organic light emitting transistors, complementary metal oxide semiconductors, complementary inverters, diodes, capacitors, sensors, D flip flops, rectifiers, and ring oscillators. The polymer is useful for preparing p-type or n-type semiconductor materials, which is useful for fabricating various organic electronic articles, structures and devices including unipolar circuitries, complementary circuitries.    ADVANTAGE - The polymer exhibits excellent charge transport characteristics in ambient conditions, chemical stability, low-temperature processability and processing versatility (e.g. printability).    DETAILED DESCRIPTION - Polymer comprising 2,7-dithia-1,3,6,8-tetraaza-dicyclopenta(a,f)naphthalene repeating unit of formula (I) is new, where the polymer has a degree of polymerization (n) of 3-1000.    Ra1 = H or Re1; and    Re1 = halo, -CN, NO2, O, -OH, -O-1-20C alkyl, -O-6-14C aryl, NH2, -NH(1-20C alkyl), -N(1-20C alkyl)2, -N(1-20C alkyl)-6-14C aryl, -N(6-14C aryl)2, -SH, -S-1-20C alkyl, -S(O)2OH, -S(O)2-O-1-20C alkyl, -S(O)2O-6-14C aryl, -C(O)OH, -C(O)-O-1-20C alkyl, -C(O)-O-6-14C alkyl, -C(O)NH2, -C(O)NH-1-20C alkyl, -C(O)N(1-20C alkyl)2, -C(O)NH-6-14C aryl, -C(O)N(1-20C alkyl)-6-14C aryl, -C(O)N(6-14C aryl)2, -C(S)NH2, -C(S)NH-1-20C alkyl, -C(S)N(1-20C alkyl)2, -C(S)N-(6-14C aryl)2, -C(S)N(1-20 alkyl)-6-14C aryl, -C(S)NH-6-14C aryl, SiH3, -SiH(1-20C alkyl)2, -SiH2(1-20C alkyl), -Si(1-20C alkyl)3, 1-20C alkyl, 2-20C alkenyl, 2-20C alkynyl, 1-20C alkyl, 2-20C alkenyl, 2-20C alkynyl, 1-20C haloalkyl, 3-10C cycloalkyl, 6-14C aryl, 6-14C haloaryl, 3-12C membered cycloheteroalkyl, or 5-14 membered heteroaryl.    INDEPENDENT CLAIMS are included for:    (1) a copolymer comprising substituted 2,7-dithia-1,3,6,8-tetraaza-dicyclopenta(a,f)naphthalene compound of formula (II);    (2) a field effect transistor device comprising a substrate, a gate electrode, a dielectric material, source and drain electrodes, and a thin film semiconductor comprising the polymer;    (3) a photovoltaic device comprising an anode (22), a cathode (26), optionally one or more anode interlayers, optionally one or more cathode inaterlayers, and a photoactive layer (24) deposited between the cathode and the anode, where the photoactive layer comprises the polymer; and    (4) an organic light emitting device comprising a substrate (28), an anode, a cathode, and an organic layer comprising the polymer, in between the anode and the cathode.    W1 = N or CH;    R1a = H, F, Cl, 3-40C alkyl, 3-40C haloalkyl or 3-40C alkenyl;    R4 = 1-40C alkyl, 1-40C alkoxy or 1-40C haloalkyl;    n = 3-1000;    x1 = optionally substituted 8-22C aryl or 8-22 membered heteroaryl comprising divalent group of formulae (aa)-(oo);    k, k1, l, l1 = -CR2=, =CR2-, -C(O)-, or -C(C(CN)2)-;    p, p1, q, q1 = -CR2, =CR2-, -C(O)-, -(C(CN)2)-, -O-, -S-, -N=, =N-, -N(R2)-, -SiR2=, =SiR2- or -SiR2R2-;    r, s = -CR2R2- or -C(C(CN)2)-;    u, u1, v, v1 = -CR2=, =CR2-, -C(O)-, -C(C(CN)2)-, -S-, -S(O)-, -S(O)2, -O-, -N=, =N-, -SiR2=, =SiR2-, -SiR2R2-, -CR2R2-CR2R2- or -CR2=CR2-;    R2 = 6-14C aryl, 5-14 membered heteroaryl (both optionally substituted with 1-4 groups comprising halo, CN, 1-40C alkyl, 1-40C alkoxy, 1-40C alkylthio or 1-40C haloalkyl), H, halo, CN, 1-40C alkyl, 1-40C alkoxy, 1-40C alkylthio, 1-40C haloalkyl, -(OCH2CH2)tOR1e, -(OCF2CF2)tOR1e, -(OCH2CF2)tOR1e, -(OCF2CH2)tOR1e, -(CH2CH2O)-R1e, -(CF2CF2O)tR1e, -(CH2CF2O)tR1e or -(CF2CH2O)tR1e;    t = 1-10;    R1e = 1-20C alkyl or 1-20C haloalkyl; and    b = 1-4.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a bulk-heterojunction organic photovoltaic device.    Solar cell (20)    Anode (22)    Photoactive layer (24)    Cathode (26)    Substrate. (28)