Process for the production of electronic or optoelectronic devices comprising the steps of (a) providing a substrate at a substrate temperature; (b) providing an ink composition at an ink temperature, said ink composition comprising one or more organic semiconductor material, one or more crystallization agent and one or more solvent; and (c) applying the ink composition to the substrate by ink-jet printing to obtain a coated substrate, wherein the crystallization agent has a melting temperature equal to or higher than the substrate temperature and a boiling temperature or sublimation temperature equal to or higher than the boiling temperature of the solvent; wherein the organic semiconducting material is a polymer or copolymer encompassing one or more repeating units selected from thiophene-2,5-diyl, 3-substituted thiophene-2,5-diyl, optionally substituted thieno[2,3-b]thiophene-2,5-diyl, optionally substituted thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, or 3-substituted selenophene-2,5-diyl; wherein the crystallization agent is benzene wherein one or more hydrogen atom is/are replaced with halogen, said halogen being selected from the group consisting of fluorine, chlorine, bromine and iodine; and wherein the solvent is selected from the group consisting of dichloromethane, trichloromethane, chlorobenzene, tetrahydrofuran, anisole, morpholine, toluene, o-xylene, m-xylene, p-xylene, 1,4-dioxane, acetone, methylethylketone, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, ethyl acetate, n-butyl acetate, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, tetraline, decaline, indane, methyl benzoate, ethyl benzoate, mesitylene and mixtures thereof. (a) providing a substrate at a substrate temperature; (b) providing an ink composition at an ink temperature, said ink composition comprising one or more organic semiconductor material, one or more crystallization agent and one or more solvent; and (c) applying the ink composition to the substrate by ink-jet printing to obtain a coated substrate, wherein the crystallization agent has a melting temperature equal to or higher than the substrate temperature and a boiling temperature or sublimation temperature equal to or higher than the boiling temperature of the solvent; wherein the organic semiconducting material is a polymer or copolymer encompassing one or more repeating units selected from thiophene-2,5-diyl, 3-substituted thiophene-2,5-diyl, optionally substituted thieno[2,3-b]thiophene-2,5-diyl, optionally substituted thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, or 3-substituted selenophene-2,5-diyl; wherein the crystallization agent is benzene wherein one or more hydrogen atom is/are replaced with halogen, said halogen being selected from the group consisting of fluorine, chlorine, bromine and iodine; and wherein the solvent is selected from the group consisting of dichloromethane, trichloromethane, chlorobenzene, tetrahydrofuran, anisole, morpholine, toluene, o-xylene, m-xylene, p-xylene, 1,4-dioxane, acetone, methylethylketone, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, ethyl acetate, n-butyl acetate, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, tetraline, decaline, indane, methyl benzoate, ethyl benzoate, mesitylene and mixtures thereof.