A recently developed methylsilses-quioxane-based photoresist is combined with direct laser writing to define 3D microstructures (see image). Because the resulting structures exhibit thermal stability above 500 degrees C without cracking or significant distortions, they should allow photonic crystals and other microstructures to be obtained from a large variety of materials. This is demonstrated by infiltrating a "woodpile" photonic crystal with silicon using chemical vapor deposition.