A molecular interface is a space where two different regions of molecular matter meet. Molecular interfaces form the active regions of organic electronic devices, such as light-emitting diodes, solar cells, and transistors. The structure and resulting properties of these interfaces determine their functionality and, thus, device performance. For decades, organic electronic devices have been based on disordered films. The opposite is true for inorganic devices, which are based on highly ordered crystalline films with epitaxial interfaces, where the crystal matrix is continuous across the interface because of their superior electronic properties. This research will explore organic epitaxial interfaces as a new paradigm for high-performance organic electronic and photonic devices. This project will develop computational tools to predict molecular interface structure and properties. Simulations will inform the selection of candidate materials for epitaxial growth and device fabrication. This work will open up a new direction in the field of organic electronics and deliver a new materials platform for more efficient devices and hybrid organic-on-inorganic integrated photonics. It will go beyond today’s trial-and-error approach to organic epitaxy by integrating first principles of quantum mechanical simulations, predictive machine learning algorithms, and experiments to validate and inform the models in a tightly coupled feedback loop.