Compositions of a mixture of a thiol material and a material that contains a reactive unsaturated carbon-carbon bond that can be polymerised to form a charge-transporting or luminescent film are described, as is an organic light-emitting diode (OLED) device comprising at least one such charge-transporting or emissive layer that has been formed by polymerising a thiol material and an ene material. The process for forming such an OLED, including the deposition of a layer of material comprising the polymerisable composition, from solution, exposing said layer to actinic radiation through a mask, and then optionally developing said film to form a photopatterned film, is also disclosed.