An organic semiconductor composition comprising a polyacene compound and an organic binder, characterised in that the organic binder is a semiconducting binder having a permittivity at 1000 Hz of between 3.4 and 8.0, wherein said polyacene compound is of formulae or: wherein R 25, R 26 and R 27 are independently selected from the group consisting of methyl, ethyl and isopropyl; and wherein R 1, R 2, R 3, R 4, R 8, R 9, R 10 and R 11 are independently selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 6 alkoxy and C 6 -C 20 aryloxy; and wherein said organic binder comprises a unit of Formula: wherein Ar 1, Ar 2 and Ar 3, which may be the same or different, each represent, independently if in different repeat units, an optionally substituted C 6-40 aromatic group being either mononuclear or polynuclear, wherein at least one of Ar 1, Ar 2 and Ar 3 is substituted with at least one polar group, and n = 1 to 20, wherein said at least one polar group is independently selected from the group consisting of nitro group, nitrile group, C 1-40 alkyl group substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C 1-40 alkoxy group substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C 1-40 carboxylic acid group optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C 2-40 carboxylic acid ester optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; sulfonic acid optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; sulfonic acid ester optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; cyanate group, isocyanate group, thiocyanate group, thioisocyanate group; and an amino group optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; and combinations thereof. wherein R 25, R 26 and R 27 are independently selected from the group consisting of methyl, ethyl and isopropyl; and wherein R 1, R 2, R 3, R 4, R 8, R 9, R 10 and R 11 are independently selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 6 alkoxy and C 6 -C 20 aryloxy; and wherein said organic binder comprises a unit of Formula: wherein Ar 1, Ar 2 and Ar 3, which may be the same or different, each represent, independently if in different repeat units, an optionally substituted C 6-40 aromatic group being either mononuclear or polynuclear, wherein at least one of Ar 1, Ar 2 and Ar 3 is substituted with at least one polar group, and n = 1 to 20, wherein said at least one polar group is independently selected from the group consisting of nitro group, nitrile group, C 1-40 alkyl group substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C 1-40 alkoxy group substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C 1-40 carboxylic acid group optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C 2-40 carboxylic acid ester optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; sulfonic acid optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; sulfonic acid ester optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; cyanate group, isocyanate group, thiocyanate group, thioisocyanate group; and an amino group optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; and combinations thereof.