In mechanochemistry, there are various approaches that bene t the engineering of solids and, additionally, they can be considered as green processes [1 7]. These are mainly three categories: #A Direct mechanosyntheses between the reagents depending upon the nature of the desired product with the use of: a) SHS reactions, b) acid-base properties of oxides; #B Modi cation of properties via high-energy milling by: a) appropriate substitution of various cations in sublattices of complex oxides e.g. with perovskite structure, b) the use of the presence of impurities from the reactor and balls in order to improve the usable features of a product; #C Activation of solids by co-milling process by: a) supporting of catalytic precursor on carrier, b and c) mechanical treatment of reactants before or after conventional synthesis process of catalysts. The practical examples are described below.