NOVELTY - Oligomeric or polymeric compound comprising a repeat unit comprising pyrazine-fused polycyclic aromatic moiety (I) or (II), is new.    USE - The oligomeric or polymeric compound is useful in: an article of manufacture comprising an electronic device, an optical device, or an optoelectronic device; a thin film semiconductor that is used in a composite, a field effect transistor device and a photovoltaic device; and in an organic light emitting device (all claimed), sensors, unipolar circuitries, complementary circuitries, photodetectors, complementary inverters, diodes, capacitors, D flip-flops, rectifiers, and ring oscillators.    ADVANTAGE - The oligomeric or polymeric compound: exhibits high carrier mobility and/or good current modulation characteristics, and/or charge transport/recombination/light emission in a light-emitting device; and possesses solution-processability and/or good stability (for example air stability) in ambient conditions.    DETAILED DESCRIPTION - Oligomeric or polymeric compound comprising a repeat unit comprising pyrazine-fused polycyclic aromatic moiety of formula (I) or (II), is new.    X = O or S;    W1 = O, S or NR1; and    R1 = 1-40C alkyl, 2-40C alkenyl, 1-40C haloalkyl (all optionally substituted with 1-10 substituents of halo, -CN, NO2 , OH, -NH2 , -NH(1-20C alkyl), -N(1-20C alkyl)2, -S(O)2OH, -CHO, -C(O)-1-20C alkyl, -C(O)OH, -C(O)-O-1-20C alkyl, -C(O)NH2, -C(O)NH-1-20C alkyl, -C(O)N(1-20C alkyl)2, -O-1-20C alkyl, -SiH3, -SiH(1-20C alkyl)2, -SiH2(1-20C alkyl), or -Si(1-20C alkyl)3, and covalently bonded to the imide nitrogen atom via an optional linker), or moiety comprising 1-4 cyclic groups (covalently bonded to the imide nitrogen atom via an optional linker and optionally substituted with 1-5 substituents of halo, oxo, -CN, NO2, OH, =C(CN)2, -NH2, -NH(1-20C alkyl), -N(1-20C alkyl)2, -S(O)2OH, -CHO, -C(O)OH, -C(O)-1-20C alkyl, -C(O)-O-1-20C alkyl, -C(O)NH2, -C(O)NH-1-20C alkyl, -C(O)N(1-20C alkyl)2, -SiH3, -SiH(1-20C alkyl)2, -SiH2(1-20C alkyl), -Si(1-20C alkyl)3, -O-1-20C alkyl, -O-1-20C alkenyl, -O-1-20C haloalkyl, 1-20C alkyl, 1-20C alkenyl or 1-20C haloalkyl).    INDEPENDENT CLAIMS are also included for:    (1) a composition comprising the oligomeric or polymeric compound dissolved or dispersed in a liquid medium;    (2) a thin film semiconductor comprising the oligomeric or polymeric compound;    (3) a composite comprising a substrate and the thin film semiconductor deposited on the substrate;    (4) a field effect transistor device comprising the thin film semiconductor;    (5) a photovoltaic device comprising the thin film semiconductor; and    (6) making an article of manufacture, comprising depositing the composition onto a substrate.