TECHNOLOGY FOCUS - ELECTRONICS - Preferred Transistor: The transistor further comprises: a gate electrode; a source electrode and a drain electrode facing each other and defining a channel region; an insulation layer that electrically insulates the source electrode, drain electrode and the gate electrode; and an active layer including the organic semiconductor polymer (I) in the channel region.    TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Preparation of the polymer (I) involves: reacting monomer of formula X1-Ar'-X2 (II) with (hetero)cyclic compounds of formulae (III) and (IV). The method further involves performing the reaction of monomer (II) with compound (III) and (IV) in the presence of a catalyst, where the catalyst is an organic metal catalyst of formulae Pd(L1)x, Pd(L2)4-yCly, Ni(L3)x' and Ni(L4)3-y'Cly'.X1, X2, Y1 and Y2=reactive groups selected from halo, trialkyl tin or borane group;Ar'=Ar1;L1 and L2=ligands selected from triphenylphosphine (PPh3), 1,4-bis(diphenylphosphine)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf), acetate (OAc), triphenyl arsine (AsPh3) and triphenylphosphite (P(OPh)3);x=2-4;y=1-3;L3 and L4=ligands selected from bis(diphenylphosphino)alkane and a cycloalkene;x'=2 or 3;andy'=1 or 2.Preferred Compound: The polymer (I) is p-type polymer. The polymer (I) is selected from 27 compounds as given in the specification e.g. compounds of formulae (IA) and (IB). The polymer (I) includes a terminal functional group selected from 4 groups as given in the specification e.g. groups of formulae (vii) and (ix).R=F or 1-20C perfluoroalkyl;c=1-5andd=1-3. Preferred Definitions:    R1-R9=F, 1-20C partially fluorinated alkyl and/or 1-20C perfluoroalkyl (CnF2n+1).    EXAMPLE - 2,2'-Bis-(5-bromo-3-dodecyl-thiophen-2-yl)-4,4'-didodecyl-(5,5')bithiazolyl (0.5 g) and bis (trimethylstannyl)thiophene (0.16 g) were introduced into a reactor under the nitrogen atmosphere and completely dissolved in anhydrous dimethylformamide (DMF) with slight heating. Then, a polymerization catalyst of tetrakis(triphenylphosphine) palladium (0) (Pd(PPh3)4)) (39 mg) was added to it and reacted at 85 degrees C for 5-6 hours. 4-Trimethylstannyl-fluorophenyl (1.1 g) was added to it and reacted for 24 hours. After the reaction, the mixed reaction solution that had cooled to room temperature was filtered. After work up, polymer of formula (IA) (where n was greater than or equal to 8) (yield 47%) having number average molecular weight of 20000 was obtained.