TECHNOLOGY FOCUS - ELECTRONICS - Preferred Device: The device (D1) further comprises a semiconducting layer, where the semiconducting layer has an average charge carrier mobility of 0.5 cm2/V.s.    TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Forming the copolymer (I) involves mixing, in an environment that is free of oxygen gas, stannite/borate compound of formula (II) with substituted 3,6-bis-(5-bromo-furan-2-yl)-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione/3,6-bis-(5-bromo-thiophen-2-yl)-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione/3,6-bis-(5-bromo-selenophen-2-yl)-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione compound of formula (III); adding a solvent that is free of oxygen gas to dissolve the mixture; adding an aryl bromide or heteroaryl bromide to the mixture and allowing the first compound to react with the second compound to form the copolymer; and collecting the copolymer. After the collecting of the copolymer, the method further includes purifying the copolymer.M'= (1,3,2)dioxaborinane-2-yl, 4,4,5,5-tetramethyl-(1,3,2)dioxaborolane-2-yl, Sn(Me)3, Sn(Bu)3, or B(OH)2;Y'=O, S or Se.Preferred Compound: The copolymer (I) is selected from 19 compounds as given in the specification e.g. compound of formula (Ia).m=1-4. EXAMPLE - In a 2-necked, 100 ml round-bottomed flask, 0.402 g of ((E)-1,2-bis(5-(trimethylstannyl)thiophen-2-yl)ethane) was combined with 0.791 g of (3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-octyldodecyl)pyrrolol(3,4-c)pyrrole-1,4(2H,5H)-dione). The flask was fitted with a condenser and flushed with Ar for 15 minutes. In a separate flask, anhydrous toluene was degassed by bubbling Ar through the solvent for 30 minutes. The reactants were dissolved in 20 ml of anhydrous, deoxygenated toluene and the reaction was treated with 5 mole % of catalyst Pd(PPh3)4 (0.045 g). The mixture was then heated to an external temperature of 95 degrees C and stirred under an Ar atmosphere. After about 24 hours, the reaction was treated with 0.776 mmol of 2-bromothiophene and stirred for about an additional 2 hours. The copolymer was collected by pouring the mixture into a solution of 50 ml of deionized water and 450 ml methanol. Any residual copolymer remaining in the flask was dissolved in CHCl3 and added into the methanol solution. The copolymer was collected by vacuum filtration and dried under a vacuum. The copolymer was then purified by Soxhlet extraction with methanol (125 ml, at 90 degrees C, for 4 hours), acetone (125 ml, at 85 degrees C for 4 hours) and hexanes (125 ml, at 90 degrees C, for 18 hours) to remove any impurities and low molecular weight oligomers. The further purified copolymer was extracted into CHCl3 (125 ml, at 90 degrees C, for 6 hours) and poured into 500 ml methanol. The copolymer was collected by vacuum filtration and dried under vacuum. The copolymer was isolated as a dark purple solid and dried under a vacuum for 18 hours to obtain copolymer. The molecular weight of the obtained copolymer was determined by conventional gel permeation chromatography (GPC) in CHCl3. The number average molecular weight (Mn); weight average molecular weight (Mw); and polydispersity index (PDI) of the obtained copolymer was found to be 48600; 517000; and 11 respectively.