Key processes in nanostructured dye-sensitized solar cells occur at material interfaces containing, for example, oxides, dye molecules, and hole conductors. A detailed understanding of interfacial properties is therefore important for new developments and device optimization. The implementation of X-ray-based spectroscopic methods for atomic-level understanding of such properties is reviewed. Specifically, the use of the chemical and element sensitivity of photoelectron spectroscopy, hard X-ray photoelectron spectroscopy, and resonant photoelectron spectroscopy for investigating interfacial molecular and electronic properties are described; examples include energy matching, binding configurations, and molecular orbital composition. Finally, results from the complete oxide/dye/hole-conductor systems are shown and demonstrate how the assembly itself can affect the molecular and electronic structure of the materials. Core of the matter: Key processes in nanostructured dye-sensitized solar cells (DSC) occur at material interfaces containing, for example, oxides, dye molecules, and hole conductors (see picture). The implementation of X-ray-based spectroscopic methods for atomic-level understanding of such properties is reviewed. Examples include energy matching, binding configurations, and molecular orbital composition.