Abstract: Semiconducting films are formed on a substrate by coating the substrate with a mixture of a semiconducting material and a substance which results in a Tg of the resulting mixture which is lower than that of the said material, and cross-linking the said material. Multilayer electronic devices may be produced by processes which comprise forming a cross-linked semiconducting film on a substrate in this way and forming a layer on the said film by solution or suspension deposition of a second film forming material in which the cross-linked semiconducting film is substantially insoluble in the solvent or suspending agent used in forming the second film. The invention may be used in making, for example, field effect transistors, light emitting diodes (LEDs), organic solar cells and organic lasers.