NOVELTY - A semiconductor device comprises a non-polymeric quinoid heteroacene compound as organic semiconductor.    USE - As semiconductor device e.g. diode, organic thin film transistor, organic field effect transistor, solar cell, or device containing a diode and/or an organic field effect transistor and/or solar cell (claimed).    ADVANTAGE - The polymeric heteroacenes based on the quinoid 1,5-dihetero-anthracene exhibits good semiconductor and applicative properties and thus can be used as organic semiconductors not only in diodes or organic light emitting diodes (OLEDs), but also in organic field effect transistors (OFETs), which are prepared as thin film transistors (OTFTs), and corresponding devices. The compound achieves semiconducting effect without the need of further components such as compounds forming a complex with the quinoid diheteroacene compounds (I) (e.g. metal or boron compounds). The semiconductor device thus usually does not contain such a component combined with the compounds in the same environment. The compounds usually are not used in the form of an adduct with another chemical entity. The compounds shows high stability against thermal and/or oxidative degradation. The organic thin film formed using the compound (I) has a thickness of 5-200 nm.    DETAILED DESCRIPTION - A semiconductor device comprises a non-polymeric quinoid heteroacene compound of formula (I) as organic semiconductor.    X = O, S or NR;    R = organic residue;    R1-R8 = R or H.    At least two of R, or R1-R8 together form at least one annealed rings which is optionally substituted carbocyclic or heterocyclic, aromatic, quinoid or aliphatic.    INDEPENDENT CLAIMS are included for the following:    (1) preparation of an organic semiconductor device involving either applying (I) (where at least one of R-R8 contains an alkyl or alkylene chain of at least 4 carbon atoms, especially 1 or 2 of R1-R8 contain a residue selected from 4-22C alkyl, 10-22C phenylalkyl, or such residues interrupted in the aliphatic part by O, S, NR10, COO, OCNR10, OCOO, OCONR10, NR10CNR10) to a suitable substrate, where the deposition of the compound is effected by vapor deposition or especially by application of a solution in an organic solvent, followed by removal of the solvent; or heating of a layer of a precursor compound of formula (III) to 60-500 degrees C; and    (2) new quinoid heteroacene compounds (IIA) and (IV).    L = 1-8C alkyl;    Xa = S or NRa;    X1 and X2 = O, S or NRa;    Ra = 1-18C alkyl, 2-18C alkenyl, 2-18C alkynyl or 4-18C aryl (all optionally substituted);    R5a-R8a = H; 1-22C alkyl, or 2-22C alkenyl (both optionally interrupted by O, S, COO, OCNR10, OCOO, OCONR10, NR10CNR10 or NR10), 2-18C alkynyl, 4-18C aryl (optionally substituted), halogen, Si(R11)3, X1R12;    R10 = H, 1-12C alkyl, or 4-12C cycloalkyl;    R11 = 1-20C alkyl or alkoxy;    R12 = Si(R11)3, optionally substituted 1-22C alkyl or 4-18C aryl; and    R9, R9a, R9b, R9c = R5a.    In (IIA) and (IV), adjacent R9 and R9c and/or adjacent R9a and R9b together form an annealed ring; and each aryl is selected from 4-18C aromatic moieties, which optionally contain, as part of the ring structure, one or 2 heteroatoms selected from O, N and S (preferably phenyl, naphthyl, pyridyl, tetrahydronaphthyl, furyl, thienyl, pyrryl, chinolyl, isochinolyl, anthrachinyl, anthracyl, phenanthryl, pyrenyl, benzothiazolyl, benzoisothiazolyl, benzothienyl); annealed rings, where present, are aromatic carbocyclic or N-heterocyclic, optionally substituted 6-membered rings; and substituents, where present, bond to a carbon atom and are selected from 1-22C alkoxy, 1-22C alkyl, 4-12C cycloalkoxy, 4-12C cycloalkyl, OH, halogen, phenyl, naphthyl; while saturated carbons also optionally substituted by oxo; 2 adjacent substituents optionally linked together, e.g. to form a lactone, anhydride, imide or carbocyclic ring.