NOVELTY - Pyrrolopyrrole derivative (I) is new.    USE - In an organic semiconductor material, layer or component; in semiconductor device which is in the form of a diode, a photodiode, a sensor, an organic field effect transistor, a transistor for flexible displays, or a (heterojunction) solar cell; and as a p-type transistor (claimed).    ADVANTAGE - The compounds have excellent solubility in organic solvents. High efficiency of energy conversion, excellent field-effect mobility, good an/off current ratios and/or excellent stability can be observed, when the compound are used in semiconductor devices or organic photovoltaic devices.    DETAILED DESCRIPTION - Pyrrolopyrrole derivative of formula (I) is new.    R1 and R2=e.g. H or 1-100C alkyl;    T1=-(Ar4)d-(Ar5)e-(Ar6)f-(Ar8)h-R4;    T2=-(Ar1)a-(Ar2)b-(Ar3)c-(Ar7)g-R3;    a=1-3;    d=0-3;    Ar1 and Ar4=bivalent group of the formula (II);    X3 and X4=e.g. N, or annulated (aromatic) heterocyclic ring system;    b, c, e, f, g and h=0-3;    Ar2, Ar3, Ar5-Ar8=Ar1, or selected from group of formulae (III)-(X);    X=e.g. -S-, or -O-;    p=0-2;    R5=25C aliphatic hydrocarbon;or    R5+R5=e.g. 7C alkylene    R6, R7, R9, R12-R19, and R21=e.g. 1-25C alkyl;or    R6+R7=e.g. 25C alkylene;    R3 and R4=e.g. H, or halo or selected from group of formulae (XI)-(XIX) or -(BU')w-N(A3)-A'3;    w=0, or 1;    BU'=bridging unit;    A3 and A'3=e.g. 6-24C aryl;    R22-R58=e.g. H or 25C heteroaromatic-aliphatic group;or    R27+R28, or R27+R58=e.g. 25C alkylene.    Provided that:    (1) e is not 0 if d is 0;    (2) the compound (I) excludes compound 3,6-bis-benzothiazol-2-yl-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione.    Full Definitions are given in DEFINITIONS field Full Definitions section. An INDEPENDENT CLAIM is included for new intermediate i.e. bromide/zinc/stannane derivative of formula (I').    T3=-(Ar4)d-(Ar5)e-(Ar6)f-(Ar8)h-X'11;    T4=-(Ar1)a-(Ar2)b-(Ar3)c-(Ar7)g-X11;    X11 and X'11=halo, (especially Br or I), ZnX12 or -SnR207R208R209;    R207-R209=H or 1-6C alkyl (where two alkyl radicals optionally form a common ring and these radicals are optionally branched or unbranched);    X12=halo (especially I, or Br) or -OS(O)2CF3, -OS(O)2-aryl (especially 4-methyl-benzenesulfonyl, -OS(O)2CH3, -B(OH)2, -B(OY1)2, compound of formula (ii) or (iii), -BF4Na, or -BF4K);    Y1=1-10C alkyl;    Y2=2-10C alkylene (such as -CY3Y4-CY5Y6-, or -CY7Y8-CY9Y10-CY11Y12-);    Y3-Y12=H, or 1-10C alkyl (especially -C(CH3)2C(CH3)2-,-C(CH3)2CH2C(CH3)2- or -CH2C(CH3)2CH2-);    Y13 and Y14=H, or 1-10C alkyl;    X12=-B(OH)2, -B(OY30)2, compound of formula (i), -BF3Na, -BF3N(Y33)4, or -BF3K;    Y30=1-10C alkyl;    Y31=2-10C alkylene;    Y33=H, or 1-25Calkyl (which may optionally be interrupted by O);    R'1=not defined.    Provided that the compound (I') excludes compounds of formulae from (I'a)-(I'f).