TECHNOLOGY FOCUS - ELECTRONICS - Preferred Component: The device in the form a solar cell comprises an anode, a cathode, and a blend of the polymer and an electron acceptor compound, the blend being provided between the anode and the cathode. It can be in the form of a battery comprising an anode, a cathode and a layer of the polymer with a gel electrolyte provided between the anode and the cathode. It can also be in the form of a transistor comprising a layer of the polymer in contact with source and drain electrodes, and further comprising a gate electrode separated from the layer of the polymer by an insulator layer.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The adjacent thiophene residues are trans- or cis- to each other with respect to the olefinic double bond. The electron acceptor compound is fullerenes or fullerene derivatives. It is preferably (6,6)-phenyl-61C butyric acid methyl ester. Preferred Method: The method is conducted in the presence of tetrakis(triphenylphosphine) palladium as catalyst. It further comprises replacing the bromine atoms with aryl groups. Preferred Definitions:    n=10-50;    Y=halo;    X=group of formula (II);    R1,R2,R5=n-hexyl;and    L,M=Br.    EXAMPLE - About 0.54 g of dibromo derivative (0.825 mmol) and 0.50 g of 1,2-bis(tributylstannyl)ethylene (0.825 mmol) were added to 10 mL of freshly distilled anhydrous toluene under nitrogen atmosphere. The mixture was stirred at room temperature for 10 minutes to yield a yellow solution. Maintaining the inert atmosphere, 0.048 g of tetrakis(triphenylphosphine) palladium(O) (0.04125 mmol, 5 molar%) was added and the subsequent mixture refluxed for 18 hours to yield a purple/black solution. After cooling to room temperature the volume was reduced to 5 ml under vacuum and a large excess of methanol added (100 mL), precipitating a dark blue/black powder. Purification was achieved by extraction with methanol, acetone and finally dichloromethane. The dichloromethane fraction (dark blue) was reduced in volume to 5 mL and added dropwise to 100 mL methanol to re-precipitate the product. Filtration and drying yielded 0.316 g of a dark blue powder. The spectrum clearly showed that the produced polymer is end-capped with tetrathiafulvalene-thiophenes and that the terminal bromine groups were intact.