Here, we systematically investigate the influence of interfacial chemistries on the electronic properties of conjugated semiconducting polymers. Specifically, the chemical functionality at the polymer/monolayer interface was modified using a versatile monolayer chemistry based on isocyanate-amine chemistry. Our previous results showed that surface bound isocyanates will not react with amines at the solid-liquid interface. However, by coupling the amine and isocyanate in solution and then depositing, silicon surfaces were prepared with functionalities such as thiophene, fluorene, pyrene, pyridine and octadecane. This strategy allowed for the production of monolayers with tailored functionality to systematically quantify, for example, the effect of a strong dipole and the interfacial chemical composition on the electronic properties of the semiconducting polymer. In one study, octadecyl triethoxy silane and 1-(3-(triethoxysilyl)propyl)-3-octadecylurea were used as dielectric modifications to evaluate the effect of a buried dipole on organic transistor performance. These chemistries provide identical polymer/ monolayer interfaces; however, the urea monolayer has a buried dipole that should affect the electrical properties of the transistor. We measure the relative surface coverage of the modified interface using NEXAFS and characterize the monolayer before coating with polymer. Transistor measurements were used to evaluate the effect of the two monolayer chemistries on the electronic properties of the semiconducting polymer. Using this chemistry, we find that strong dipoles buried in the dielectric layer can strongly influence the device properties.