Patterning functional materials is a central challenge across many fields of science. The ability to lithographically fabricate micro- and nanostructures has been one of the most impactful technological breakthroughs of the last century. In part due to the complexity of the chemical processes in photoresists, there is a limited variety of materials that can currently be patterned by photolithography. We report a negative tone photoresist using a photoactivated olefin metathesis catalyst, which can be quickly prepared in a one-pot synthesis from commercially available starting materials. The resist is based on a ruthenium vinyl ether complex, widely regarded as inactive toward olefin metathesis. The combination of this photoactivated catalyst with the fidelity and functional group tolerance of ruthenium-mediated olefin metathesis enables a host of new possibilities for photopatterned materials.