The results of my research in the fields of theoretical studies and computer modeling of supramolecular chemical systems were presented. The main attention was focused on theoretical studies in the following topics: cycloaddition and nucleophilic addition reactions involving substrates with multiple CC and CN bonds, their mechanisms, driving forces, kinetics and thermodynamics; the consideration of the catalysis of hydrocarbons oxidation processes and their conversion to alcohols, ethers, aldehydes, ketones and carboxylic acids; investigations of various unusual types of non-covalent interactions (from quite trivial hydrogen bonds to more exotic σ-hole, π-hole and metallophilic interactions) in organic, organometallic and coordination compounds. Some fundamental issues of supramolecular chemical systems were also discussed (e.g., structure and properties of chemical compounds and their supramolecular associates; conformational transitions and rotation barriers of functional groups; nature of chemical bonds; orbital and charge factors; photophysical properties).