We will design and grow molecular covalent crystals with different hybridizations and geometries, such as covalent organic frameworks and graphene nanoribbons, using the pyrolytic vapor polymerization (PVP) approach that we developed. Molecular precursors are sealed under high vacuum in a quartz tube and then subjected to a temperature gradient. The chemical reactions occur on the source side (hot zone) and crystallization occurs on the sink side (cold zone).