NOVELTY - Dithienopyrrole-containing copolymers (A), where D comprises a first monomer radical having pyrrole structure (a), is claimed.    USE - (A) is useful in article (claimed). (A) is useful as p-type and donor compounds in semiconductors for organic photovoltaic applications, such as solar cells or transistors, and organic field effect transistors. (A) is useful for the manufacture of affordable, highly efficient organic photovoltaic cells, organic field effect transistors and other organic semiconductors.    ADVANTAGE - (A) has excellent hole-conductivity, which may improve through oxidation. (A) has low bandgap and high absorbance and increases the efficiency of a transistor or a solar cell.    DETAILED DESCRIPTION - Dithienopyrrole-containing copolymers (A) of formula (Y1-(D1f)-((A)-(D))n-(A1g)-Z) (I) or (V1-(Tl)a-(D)b-(Tm)c-((Ap)-(Tl)-(D)-(Tm))n-(Ap)d-(Tl)e-W1) (II), where D comprises a first monomer radical having pyrrole structure of formula (a), is claimed.    R1 = 1-20C alkyl, 1-20C heteroalkyl, 1-20C F-alkyl, 1-20C O-alkyl, 1-20C S-alkyl, 6-20C aryl, or 1-20C heteroaryl;    A = a second monomer radical different from D which forms a copolymer with D;    T = thiophene monomer radical or thiophene oligomer radical (both optionally substituted by H, 1-20C alkyl, 1-20C heteroalkyl, 1-20C F-alkyl, 1-20C O-alkyl, 1-20C S-alkyl, 6-20C aryl and/or 1-20C heteroaryl);    a, b, c, d, f, g, = 0 or 1; either    l, m, p = 0 or 1; or    l+m+p = 1-3;    V1, W1, Y1, Z = H, halo, 6-20C aryl, 1-20C heteroaryl, 1-20C alkyl, functional group comprising B(OR)(OR1a), -COOR, -CONRR1a, -CN, -OR, -OCOR, -SCSR, -CSSR, -SO3R, SO3NRR1a, -COR, OSO2R, OSO3R, -CSR, -NRR1a, -NRR1aR1b, NRCOR1a, -NO, -NO2, -NCO, -NCS or 6-20C aryl with one or more functional groups, 1-20C heteroaryl with one or more functional groups, 1-20C alkyl with one or more functional groups;    R, R1a, R1b = H, 1-20C alkyl, 1-20C heteroalkyl, 1-20C F-alkyl, 6-20C aryl, 1-20C heteroaryl or a counterion forming a salt; and    n = 1-100.    INDEPENDENT CLAIMS are included for: a method of forming (I) comprising: either (a) providing a first monomer of formula (X1-D-X2) (aa), (b) reacting the first monomer (if X1 and X2 are hydrogen) with at least one first reagent by forming an intermediate reaction product, and reacting the intermediate product with a second monomer radical A in the presence of a polymerization catalyst to form a dithienopyrrole-containing copolymer intermediate, (c) reacting the first monomer (if neither X1 nor X2 are hydrogen) with at least one first reagent by forming an intermediate reaction product and reacting the first monomer with A in the presence of a polymerization catalyst to form a dithienopyrrole-containing copolymer intermediate, and (d) reacting the dithienopyrrole-containing copolymer intermediate with a reaction terminating agent; or (a1) reacting (aa) with a second monomer of formula (Y1-Tl-Ap-Tm-Y2) in the presence of a polymerization catalyst to form a dithienopyrrole-containing copolymer intermediate, or reacting a first monomer of formula (X1-Tl-D-Tm-X2) with a second monomer of formula (Y1-Ap-Y2) in the presence of a polymerization catalyst to form a dithienopyrrole-containing copolymer intermediate, or reacting a first monomer of formula (X1-Th1-D-Th2-X2) with a second monomer of formula (Y1-Tj1-Ap-Tj2-Y2) in the presence of a polymerization catalyst to form a dithienopyrrole-containing copolymer intermediate (where Th-Tj = Tl and Tj-Th = Tm, and Th is either Th1 or Th2, and Tj is either Tj1 or Tj2), and (b1) reacting the dithienopyrrole-containing copolymer intermediate with a reaction terminating agent.    X1, X2 = H, halo, metal leaving group or non-halogen electron withdrawing group.