NOVELTY - Pyrene derivative is new.    USE - As organic semiconductor compound used as transistor of electronic device (Claimed); for fabricating solar cell, memory device, an organic light emitting diode (OLED), photosensor, and laser device.    ADVANTAGE - The organic semiconductor compound (I) has excellent charge mobility. The compound has an excellent coplanarity due to the pyrene mother-structure and has organic semiconductor characteristics due to the thiophenyl ring group or thiazolyl ring group structure fused with the pyrene mother-structure. The compound having an excellent coplanarity easily transfers charge between molecules to provide good semiconductor characteristics, so it can be effectively used in a transistor. The compound can be applied to solar cell since it has good miscibility with fullerene, graphene. The hetero ring group in the compound (I) can decrease the highest occupied molecular orbital (HOMO) level, improve the oxidation stability and the electrical reliability of the compound or the organic semiconductor polymer obtained from the same, and increase the coplanarity, so as to increase the interaction between molecules. Therefore, it can be anticipated to improve the carrier mobility. The organic semiconductor polymer has a number average molecular weight (Mn) of 5000-200000, so a solution process such as inkjet printing or drop-casting can be performed easily. An active layer can be prepared by a solution process of a composition including an organic semiconductor compound or polymer such as screen printing, printing, spin coating, dipping, and ink jetting. When the active layer is obtained by a solution process, the process cost can be reduced.    DETAILED DESCRIPTION - Pyrene derivative of formula (I), as organic semiconductor compound, is new.    X1 and X4=S, N or CR50;    X2=S or CR50;    X3=S or CR50;    R50=1-20C linear or branched alkyl or 6-20C aryl (both optionally substituted) or H;    R1-R6=1-20C linear or branched alkyl, 3-20C cycloalkyl, 1-20C alkoxy, 3-20C cycloalkyloxy, 6-30C aryl, 6-30C aryloxy or 2-30C heteroaryl (all optionally substituted), H, halo, 2-30C heteroaromatic ring group including at least one electron withdrawing imine nitrogen atom, 2-30C heteroaromatic ring group including at least one sulfur atom, NR51R52, C(O)OR53, and/or C(O)NR54R55;or    two adjacent substituents of R1-R6 linked to each other=thiophenyl ring group fused with a pyrene moiety or a thiazolyl ring group fused with a pyrene moiety;    R51-R55=H, 1-20C linear or branched alkyl, 3-20C cycloalkyl, 6-30C aryl or 2-30C heteroaryl (all optionally substituted);    a=single or double bond;    R7 and R8=1-20C linear or branched alkyl, 3-20C cycloalkyl, 1-20C alkoxy, 3-20C cycloalkyloxy, 6-30C aryl, 6-30C aryloxy or 2-30C heteroaryl (all optionally substituted), H, halo, 2-30C heteroaromatic ring group including at least one electron withdrawing imine nitrogen atom, 2-30C heteroaromatic ring group including at least one sulfur atom, NR51R52, C(O)OR53, and/or C(O)NR54R55.    Provided that    (1) at least one of X1 and X2 is S;    (2) at least one of X3 and X4 is S;    (3) when at least one of X1 and X2 is S, then the other one of X1 and X2 is CR50;    (4) when at least one of X3 and X4 is S, then the other one is CR50;    (5) at least one of R1 to R6 is one of 2-30C heteroaromatic ring group including at least one electron withdrawing imine nitrogen atom; and    (6) two adjacent substituents of R1 to R6 are linked to each other to provide one of a thiophenyl ring group fused with a pyrene moiety and a thiazolyl ring group fused with a pyrene moiety.    INDEPENDENT CLAIMS are included for the following:    (1) an organic semiconductor polymer (A1) including a structural unit having formula (V);    (2) a transistor (10) comprising the organic semiconductor compound (I) or the polymer (A1); and    (3) an electronic device comprising the organic semiconductor compound (I), or the polymer (A1).    Ar1 and Ar2=6-30C aromatic ring, 4-14C heteroaromatic ring or 6-30C condensed polycyclic group (all optionally substituted);    p and q=0-10.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of the transistor.    Transistor (10)    Substrate (12)    Gate electrode (14)    Insulation layer (16)    Source electrode (17a)    Drain electrode (17b)    Active layer (18)