Mechanochemical reactions by milling have recently emerged as excellent, rapid and cleaner alternative to conventional solution synthesis in a number of areas, from nanomaterials and alloys to supramolecular, organic materials and metal-organic frameworks. The area flourished after the introduction of new techniques, liquid-assisted grinding and ion- and liquid assisted grinding, involving additives in the reaction mixtures. Despite a growing rate of published articles, the means of controlling the basic milling reaction conditions, such as temperature and pressure in the vessel, is still not a part of standard milling procedures. Moreover, understanding of the effect of reaction conditions and additives on milling-reaction mechanisms is currently on speculative level. The main objective of this project proposal is to explore fundamental aspects of mechanochemical solid-state reactions under controlled pressure and in a range of temperatures. We will employ different gases (with special focus on environmentally relevant gases such as carbon dioxide, methane and sulfur- or nitric oxides) as reacting agents and templates for the synthesis of porous metal-organic and covalent organic frameworks, to selectively bind pollutant gases to nonporous coordination compounds or to functionalize carbon atoms in organometallic compounds. To successfully implement the objectives of this project proposal, we will develop milling vessels where the described reaction conditions can be achieved. Mechanistic aspects of gas-solid milling reactions will be studied by our novel in situ and real-time monitoring techniques. The experience and knowledge acquired by the project implementation will be applied to mechanochemical formation of target materials in order to broaden understanding and application scope of mechanochemical reactivity. The project results are expected to have a strong transformative effect on solid-state reactivity in a research laboratory as well as in chemical industry.