A brief overview of the main achievements of the Computational Chemistry Group of the Laboratory of Quantum Chemistry of the Institute of Chemistry over the last 10 years is outlined. First of all, some progress was made in the development of the theory ofJahn-Teller effect (JTE) and pseudo JTE (PJTE), which was the main scientific theme of the laboratory for many years since its organization at the Institute of Chemistry. A new approach to handle instabilities and structural changes in molecular systems due to their interaction with another molecular systems or with a solid is worked out based on an approximate evaluation of the JT and PJT effects in systems with fractional charges that occur due to orbital charge transfers. Applications to specific coordination compounds demonstrate the predictive power of the theory and its efficiency in rationalization of the experimental data (see, for example, [1-3]). Over the last five years, a new method has also been developed to analyze the influence of changes in the PJTE in molecular systems by means of external perturbations (such as excitation, oxidation, reduction, chemical substitution) on the subsequent change in their geometry and related properties. The method provides some clues to manipulate the structure and properties of molecular system [4-8]. Based on quantum-chemical calculations, the mechanisms of a number of chemical reactions have been clarified,among them are: decomposition of hydrogen peroxide catalyzed by Fenton's reagent, and manganese mono- and binuclear complexes [9,10], chemical activation and hydrogenation of white phosphorus in reaction with rhodium trihydride complex [11], accelerateddecomposition of fungicides on the wet TiO2 surface under solar irradiation [12], etc. Some progress has also been made in a comparative study of the antioxidant activity of dihydroxyfumaric acid and its derivatives in the reaction with the stable radical DPPH* [13]. Moreover, the role of additives (such as TiO2) in enhancing the antioxidant properties of organic compounds has been clarified. As part of the study “structure-properties”, for a number of organic liquids the regression equations for the “structure-surface tension” relationships were developed, which allow us to bind this macromolecular parameter of liquids with the parameters of their electronic structure, which in turn can be estimated using quantum chemical calculations [14,15]. The perspectives for the development of this branch of physical chemistry in our country are also discussed.