In this lecture I will present an introductory overview of power, capabilities and limitations of modern quantum chemical techniques for studying reactivity and chemical properties of different classes of inorganic materials ranging from organometallic complexes to MOFs and zeolites. The subjects discussed in the lecture will include the methodological aspects of computational chemistry crucial for modeling extended chemical systems as well as recent relevant examples of application of computational methodologies for developing new concepts of catalytic reactivity. Emphasis will be made on the complementary use of experimental and computational approaches for unraveling molecular-level phenomena defining the specific functions of the materials.​