NOVELTY - Diketopyrrolopyrrole compound (I) is new.    USE - In the organic semiconductor material for semiconductor device selected from diode, photodiode, sensor, organic field effect transistor, transistor for flexible displays, Parallax Radio Frequency Identification (RFID) Reader, or heterojunction solar cell (claimed).    ADVANTAGE - The compound has excellent solubility in organic solvent; has high efficiency of energy conversion; has excellent field-effect mobility; and has good on/off current ratios and has excellent stability.    DETAILED DESCRIPTION - Diketopyrrolopyrrole compound of formula (I) is new.    R1 and R2=1-100C alkyl (optionally substituted by halogen atoms, hydroxyl groups, nitro groups, -CN, or 6-24C aryl groups and/or interrupted by -O-, -COO-, -OCO-, or -S-), 7-100C arylalkyl (optionally mono to penta substituted by 1-8C alkyl, 1-8C alkoxy, CF3 or F), 5-12C cycloalkyl (optionally mono to tri substituted by 1-8C alkyl or 1-8C alkoxy), 6-24C aryl group, in particular phenyl or 1- or 2-naphthyl (which is optionally mono to tri substituted by 1-8C alkyl, 1-8C thioalkoxy, or 1-8C alkoxy)-COOR103, carbamoyl group, or pentafluorophenyl;    a=1, 2 or 3;    e=1, 2 or 3;    b, c, d, f, g and h=0, 1, 2 or 3;    Ar1 and Ar5=selected from 36 groups as given in specification e.g. group of formulae (i), (ii), (iii), (iv) or (v);    R3 and R'3=3-25C alkyl (optionally interrupted by oxygen or sulfur atoms), H, halogen, halogenated 1-25C alkyl, CF3, CN, 7-25C arylalkyl, or 1-25C alkoxy;    R4, R'4, R5, and R'5=3-25C alkyl (optionally interrupted by oxygen or sulfur atoms), H, halogen, halogenated 1-25C alkyl, CF3, CN, 7-25C arylalkyl, or 1-25C alkoxy;    R114=3-25C alkyl (optionally interrupted by oxygen, or sulfur);    R7, and R'7=3-25C alkyl (optionally interrupted by oxygen or sulfur atoms), H, or 7-25C arylalkyl;    Ar2, Ar3, Ar4, Ar6, Ar7 and Ar8=Ar1, -C?=C-, trans -C(R104)=C(R'104)-, or cis -C(R104)=C(R'104)-;    R104 and R'104=hydrogen, CN, COOR103, or 1-25C alkyl group;    R103 and R'103=6-24C aryl or 2-20C heteroaryl (both optionally substituted), 3-25C alkyl, 1-25C alkyl interrupted with O, or 7-25C arylalkyl;    R13 and R14=H, CN, 0-25C aliphatic hydrocarbon, alkoxy or 0-25C alkenyloxy, halogen, a cycloaliphatic, cycloaliphatic-aliphatic, aromatic, aromatic-aliphatic, heteroaromatic or 0-25C heteroaromatic-aliphatic group, 1-25C alkyl group which is substituted by halogen atoms, CF3, or 13 groups of formulae as given in specification e.g. group of formula (vi), (vii), (viii), (ix), or (x);    w=0 or 1;    B'U'=bridging unit;    A3 and A'3=6-24C aryl group, or 2-26C heteroaryl group (all optionally substituted);    R22-R33 and R58=H, CN, 0-25C aliphatic hydrocarbon, 1-25C alkyl group which is substituted by halogen atoms, CF3, alkoxy or 0-25C alkenyloxy, halogen, cycloaliphatic, cycloaliphatic-aliphatic, aromatic, aromatic-aliphatic, heteroaromatic or 0-25C heteroaromatic-aliphatic;    R27+R28, or R27+R58=0-25C alkylene or 0-25C alkenylene which may be both bonded via oxygen or sulfur to the thienyl residue.    Provided that at least one of Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7 and Ar8 is substituted by CN; or R13 and R14 are CN, or substituent, which is substituted by CN. INDEPENDENT CLAIMS are included for the following:    (1) an organic semiconductor material, layer or component, comprising the compound (I);    (2) a semiconductor device comprising compound (I), or organic semiconductor material, layer or component;    (3) preparation of an organic semiconductor device, involving forming organic semiconductor layer by applying a solution and/or dispersion of compound (I) in an organic solvent to a suitable substrate and removing the solvent; or forming organic semiconductor layer by vacuum vapor deposition of compound (I); and    (4) preparation of compound (I).