NOVELTY - Fused polycyclic heteroaromatic compounds (I) are new.    USE - (I) are useful in an organic thin film and an electronic device, which is a transistor, organic LED, photovoltaic device, solar cell, laser device, memory or sensor (all claimed), where the organic thin film is useful to organic semiconductor layer for electronic device or carrier transport layer (e.g. channel layer).    ADVANTAGE - (I): have compact planar structure in which seven or more aromatic rings are fused together; exhibit higher charge mobility; and enable the use of deposition process or room-temperature solution process when applied to devices, thus provide improved processability and workability.    DETAILED DESCRIPTION - Fused polycyclic heteroaromatic compounds (I) are new.    Ar1 = 6-30C aromatic cyclic group (optionally substituted);    X1-X4 = O, S, Se, Te, N-R1a or CR1b;    R1a, R1b = 1-30C alkyl, 7-30C arylalkyl, 6-30C aryl, 1-30C alkoxy, 6-30C aryloxy (-OR11), 4-30C cycloalkyl, 4-30C cycloalkyloxy (-OR12) or 2-30C heteroaryl (all optionally substituted), H, acyl (-C(=O)R13), sulfonyl (-S(=O)2R14) or carbamate (-NHC(=O)OR15);    R11 = 6-30C aryl (optionally substituted);    R12 = 2-30C 4-30C cycloalkyl (optionally substituted);    R13-R15 = 1-30C alkyl (optionally substituted);    at least one of X1 and X2, at least one of X3 and X4 = O, S, Se, Te or N-R1a;    X5, X6 = O, S, Se, Te, N-R1a or CR1bR1c;    R1a-R1c = linear or branched 1-30C alkyl, 7-30C arylalkyl, 6-30C aryl, 1-30C alkoxy, 6-30C aryloxy OR11, 4-30C cycloalkyl OR12 or 2-30C heteroaryl (all optionally substituted), H, acyl C(O)R13, SO2R14 or carbamate NHC(O)OR15; and    R1-R6 = linear or branched 1-30C alkyl, linear or branched 2-30C alkenyl, 2-30C linear or branched 2-30C alkynyl, 2-30C arylalkyl, 2-30C heteroarylalkyl, 2-30C alkylheteroaryl, 2-30C heterocycloalkyl, 6-30C aryl or 2-30C heteroaryl (all optionally substituted), H or halo.    An INDEPENDENT CLAIM is also included for an electronic device comprising (I).