NOVELTY - Fused polycyclic heteroaromatic compounds (I) comprising substituted fused pentacyclic compounds (IA) and/or (IB) are new.    USE - (I) are useful in an organic thin film and an electronic device which is a transistor, an organic-LED, a photovoltaic device, a solar cell, a laser device, a memory or a sensor (all claimed).    ADVANTAGE - (I) exhibit a relatively high charge mobility and enable the use of a deposition process or a room-temperature solution process when applied to devices, thus realizing the improved processability and workability, and the reduced process cost in fabricating device.    DETAILED DESCRIPTION - Fused polycyclic heteroaromatic compounds (I) comprising substituted fused pentacyclic compounds of formulae (IA) and/or (IB) are new.    X1, X2 = O, S, Se, Te or N-R1a;    X3, X4 = O, S, Se, Te, N, N-R1a or CR1b;    R1a, R1b = optionally branched 1-30C alkyl, 7-30C arylalkyl, 6-30C aryl, 1-30C alkoxy, 6-30C aryloxy (-OR11), 4-30C cycloalkyl, 4-30C cycloalkyloxy (-OR12), 2-30C heteroaryl (all optionally substituted), acyl (-C(=O)R13), sulfonyl (-S(=O)R14), carbamate (-NH2COOR15), or H;    R11 = optionally substituted 6-30C aryl;    R12 = optionally substituted 4-30C cycloalkyl;    R13 = optionally substituted 1-30C alkyl;    R14 = optionally substituted 1-30C alkyl;    R15 = optionally substituted 1-30C alkyl; either    R1-R10 = optionally branched 1-30C alkyl, optionally branched 2-30C alkenyl, optionally branched 2-30C alkynyl, 7-30C arylalkyl, 2-30C heteroarylalkyl, 2-30C alkylheteroaryl, 5-30C cycloalkyl, 2-30C heterocycloalkyl, 6-30C aryl, 2-30C heteroaryl (all optionally substituted), H, -F, -Cl, -Br or -I; or    at least one of R1R2 and R2R3 = aromatic ring, heteroaromatic ring or alicyclic ring fused with X3-containing ring; or    at least one of R4R5 and R5R6 = aromatic ring, heteroaromatic ring or an alicyclic ring fused with X4-containing ring; and    n, m = 0 or 1.    Provided that: X3 and X4 are not simultaneously CR1b; and n and m are not simultaneously 1.