TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Device: The device is configured as an organic photovoltaic device comprising an anode (22), a cathode (26), optionally greater than or equal to 1 anode interlayer, optionally greater than or equal to 1 cathode interlayer, and in between the anode and the cathode there is the polymeric semiconductor component (24). The organic photovoltaic device is a bulk heterojunction photovoltaic device. The polymeric semiconductor component is photoactive and the polymer (P1) is present in a blend material, where the polymer (P1) functions as an electron-donor compound and the blend material further comprises an electron-acceptor compound, where the electron-acceptor compound is a fullerene compound; or the electron-acceptor compound is an electron-transporting polymer (preferably electron-transporting polymer comprises a bis(imide)arene unit, and the arene group in the bis(imide)arene unit is naphthalene).    TECHNOLOGY FOCUS - POLYMERS - Preferred Compounds: The substituted tricyclic repeating unit (M1b) is selected from 20 groups as given in the specification e.g. groups of formulae (Ie), (If), (Ig), (Ih) and (Ii). The polymer (P1) further comprises a repeating unit (M2) that is different from the repeating unit (M1a) and the repeating unit (M1b). The repeating unit (M2) comprises an electron-poor polycyclic heteroaryl group, and is selected from 6 groups as given in the specification e.g. groups of formulae (IIa) and (IIb).R'c=F, Cl, -CN, or L'aR'a;L'a=-O-, -S-, -Se-, -C(O)-, -OC(O)-, -C(O)O-, or covalent bond;R'a=1-40C (halo)alkyl, 2-40C alkenyl, or 2-40C alkynyl;d=1-5;d'=1-3;Ar=optionally substituted 5-8 membered heteroaryl;R1 and R2=H, halo, CN, or L'bR'b;L'b=-O-, -S-, -Se-, -C(O)-, -OC(O)-, -C(O)O-, divalent 1-20C (halo)alkyl, or covalent bond;R'b=H, 1-40C (halo)alkyl, 2-40C alkenyl, 2-40C alkynyl, or optionally substituted 6-14C aryl or 5-14 membered heteroaryl;m and m'=0-2.Preferred Components: The polymer (P1) is selected from 5 polymers as given in the specification e.g. polymer of formula T1-T2. The polymer (P1) has a molecular weight of 3000-300000.T1=group of formula (iia);T2=group of formula (iib);R'd=H or Cl;R1a, R3 and R4=H, F, Cl, or CN (preferably R1a is F, Cl, or CN);R13 and R14=H, F, Cl, R15, OR15, or SR15;R15=1-20C (halo)alkyl, or 1-20C alkenyl;c1=0-2;d1=1-3;x and y=mole fraction selected from 0.05-0.95;x+y=1.The repeating unit comprising x mole fraction of the polymer and the repeating unit comprising y mole fraction of the polymer are repeated in a random manner. Preparation (disclosed): The preparation of the polymer (P1) involves: reacting a trimethylstannanyl derivative of repeating unit (M1a) or (M1b) with a brominated repeating unit comprising substituted 2H-benzotriazole compound as building blocks in presence of Pd2(dibenzylideneacetone(dba))3 and P(ortho-tolyl(o-Tol))3, by Stille coupling or Suzuki coupling reactions. Preferred Definitions:    L'=-O-, -S-, -OC(O)-, divalent 1-20C alkyl, or covalent bond;    W'1, U'1 and U'=S;    V'1 and V'=CH or CHCl;    W'=CH;    L1=-O-, -S-, -OC(O)-, or divalent 1-20C alkyl.    EXAMPLE - No suitable example given.