Sure. Mylar was used on the Echo satellites for passive microwave reflection and experienced solar sail effects, so the idea's not incompatible with reality. This assumes you're using frequencies suitable for use with mylar or kapton. (A sail made out of meta-materials on the other hand...) The only issue would be figuring out how to maintain the proper geometry for a reflector dish when you want to transform it to that purpose. Or if you want to leave it permanently in that configuration, the focal point might get overheated by solar energy, but maybe that would be useful too.
Et tu BAUT? Quantum mutatus ab illo.