In this thesis impedance spectroscopy is investigated as possible characterization method for transport properties in porous materials. For this purpose, examples were analysed in the field of sensors and proton conductors, respectively. Nanostructured indium oxide is a promising material for photo-enhanced resistive semiconducting gas sensors. Photo-activation and subsequent regeneration affects the electronic properties of the material which is investigated by impedance analysis of macroporous and mesoporous indium oxide. Due to different morphological and structural material properties various effects with different time scales can be observed during photo-activation and regeneration. Furthermore, proton conduction mechanism of two novel, microporous metal organic frameworks (MOFs) are investigated. Proton conductive MOFs can potentially be used as materials for applications in the field of proton exchange membrane fuel cells. For impedance measurements of the MOFs a measurement setup which enables impedance analysis at various operating parameters is established and characterized by reference samples (Nafion117 membranes). Due to inherent crystallinity and suitable contacting on interdigital electrodes impedance analysis of single crystals of the novel MOFs is performed. Thus, anisotropic effects are shown and the underlying proton conduction mechanisms are elucidated.