The control of hybrid interfaces in polymer-based electronic devices may be enabling in many applications. The engineering of hybrid interface involves (requires) an understanding of the electronic structure of materials - one organic and one inorganic - that form the two halves of hybrid interfaces, as well as the electronic and chemical consequences of the coupling of the two. Although much literature exists describing the interfaces between vapor-deposited organic molecules and model molecules for polymers on the surfaces of clean metals in ultrahigh vacuum, few studies have been reported on spin-coated, semiconducting polymer films on realistic substrates. Spin coating in an inert atmosphere (or even air) is a central part of the process of the fabrication of polymer-based light-emitting devices and other modern polymer-based electronic components. Here, work on the electronic structure of semiconducting (conjugated) polymer films spin-coated onto selected inorganic substrates, carried out using ultraviolet photoelectron spectroscopy, is reviewed and summarized to generate a generalized picture of the hybrid interfaces formed under realistic device fabrication conditions. © 2004 Materials Research Society.