NOVELTY - Electronic or optoelectronic device comprises a non-polymeric compound incorporating one or more polymeric groups (I), where the non-polymeric compound is an electron acceptor or is an electron donor in an active layer of the electronic or optoelectronic device.    USE - The electronic or optoelectronic device is useful as solar cell (claimed) and transistors.    ADVANTAGE - The electronic or optoelectronic device is cost-effective, and has excellent photovoltaic properties.    DETAILED DESCRIPTION - Electronic or optoelectronic device comprises a non-polymeric compound incorporating one or more polymeric groups of formula (I), where the non-polymeric compound is an electron acceptor or is an electron donor in an active layer of the electronic or optoelectronic device.    M = S, O or N-R1;    R1 = H, 1-30C alkyl or 6-30C aryl; and    X1, Y1 = CH or N (where when X1 is CH and Y1 is N, when X1 is N and Y1 is CH).    INDEPENDENT CLAIMS are included for:    (1) substituted hetero aryl compounds of formulae (II)-(IV);    (2) a device comprising (a) a first hole-collecting electrode optionally coated onto a transparent substrate, (b) an optional layer or layers adjacent to the first electrode, such as an electron-blocking, exciton-blocking, or hole-transporting layer, (c) a layer comprising a mixture of an electron acceptor material and an organic non-polymeric electron donor, where the electron donor comprises (II)-(IV), (d) an optional layer or layers such as hole-blocking, exciton-blocking, or electron transporting layers, and (e) a second electron-collecting electrode; and    (3) a device-II comprising a dielectric substrate, an optional layer or layers adjacent the dielectric substrate, to modify the surface energy of the dielectric and/or to facilitate deposition of the active layer, an active layer comprising an organic non-polymeric electron transporting material comprising (II)-(IV), and a metal electrode to facilitate charge injection and collection.    X2-X4, Y2-Y4, = CH or N (where when X2-X4 is CH and Y2-Y4 is N, when X2-X4 is N and Y2-Y4 is CH);    n = 0-5;    A1, B1 = 6-30C aryl, 6-30C heteroaryl, 6-20C aryl, 6-20C heteroaryl, 6-10C aryl or 6-10C heteroaryl (all optionally substituted);    B2 = 6-30C aryl, 6-30C heteroaryl, 6-20C aryl, 6-20C heteroaryl, 6-10C aryl, 6-10C heteroaryl (all optionally substituted), H, F or 1-16C alkyl;    H1 = A1, -B1-B2, -A1-B1-B2 or thiophene group of formula (a1);    K1 = aryl or heteroaryl, such as 6-30C aryl, 6-30C heteroaryl, 6-20C aryl, 6-20C heteroaryl, 6-10C aryl, or 6-10C heteroaryl (all optionally substituted);    E1 = absent or optionally substituted aryl or heteroaryl;    D1 = optionally substituted aryl or heteroaryl;    D2 = 1-16C alkyl, 1-16C aryl, 1-16C heteroaryl (all optionally substituted), H or F;    CORE = 2,2',7,7'-yl-9,9'-spirobi(fluorene), 3,3',7,7'-yl-5,5'-spirobi(dibenzo(b,d)silole), 2,2',6,6'-yl-4,4"-spirobi(cyclopenta(l,2-b:5,4-b')dithiophene) or 2,2',6,6'-yl-4,4'-spirobi(silolo(3,2-b:4,5-b')dithiophene);    F1, G1 = optionally substituted aryl or heteroaryl; and    G2 = H, F, 1-16C alkyl, or optionally substituted aryl or heteroaryl.