****

We have succeeded to convert diketone precursors of pentacene and anthracene derivatives to the corresponding acenes by photoirradiation in solution and on film.
This method is very useful for the preparation of organic semiconductive films by solution process.
Utilization of light allows us to prepare films on flexible plastic substrate and make patterning by masking.
We are preparing improved organic semiconductive compounds photochemically and are going to study their application to organic field effect transistors and organic thin film solar cells.