Polymers provide extraordinary opportunities for functionalizing surfaces and creating thin films for integration into flexible devices. Vapor deposition is the method of choice for polymers having limited solubility or if the object to be coated degrades or swells upon exposure to solvent. Indeed, fluoropolymers, cross-linked materials, and electrically conducting polymers are three examples of organic materials which having little if any solubility, but which have been successful deposited by two new vapor phase methods: initiated chemical vapor deposition (iCVD) and oxidative chemical vapor deposition (oCVD). By depositing polymers from the vapor phase, many wetting and solution effects are avoided, and conformal films can be created. The iCVD method is a platform technology which has produced more than 40 different homopolymers. Random copolymers, alternating copolymers, and grafted polymer chains have all been demonstrated using the iCVD method. Surface properties achieved include non-leaching antimicrobial layers, flexible dielectrics with low leakage current, and coatings with specific ligand binding capability on porous substrates and particles, superhydrophobicity, and superhydrophilicity. Engineering of iCVD coatings has led to extremely stable and flexible biopassivation coatings for neural implants, reversible swellable hydrogel layers, and enteric coatings of drug particles for pH sensitive release. Mechanistic understanding of the oCVD growth mechanism led to the ability to propagate conductive polymer chains directly from the growth surface with the use of any additional linker molecules. The creation of durable covalent linkages between the substrate and the surface functionalization layer affords excellent adhesion and also enables 60 nm lithographic pattern formation. The demonstration of patterns in conducting polymer patterns grafted onto common plastic substrates is a potential breakthrough for integrated circuitry for flexible electronics where mechanical robustness is extremely important, requiring excellent interfacial properties and adhesion. Each organic thin film synthesized by iCVD and oCVD displays a well-defined chemical structure as a result of selectively limiting the reaction pathways available during processing through a judicious choice of reactants and minimizing the energy input that drives the CVD chemistry. The exquisite control over composition and conformality achieved by these new vapor phase methods enables precise organic functionality to be designed and applied to almost any type of substrate. The fundamental understanding of the processes accelerates both discovery of and scale-up.