In times of shortage of resources and climate modification, chemistry can deliver solutions and counteract our today's challenges. Global warming, caused by increasing emissions of greenhouse gases such as carbon dioxide (CO₂), methane and others, has been recognized as a serious environmental problem. A possible solution is the reduction of CO₂ emissions, mainly through the reformulation of the processes for energy production from carbonaceous resources. Another option is the CO₂ utilization as a renewable resource, i.e. the reuse of existing CO₂ as a source of carbon for producing chemicals. Nowadays, the utilization of CO₂ as a new feedstock for commodity and specialty chemicals is intensively discussed. The advantages in the development of reliable methods to fixate and activate the CO₂ molecule are mainly two : 1- the alleviation of climate modifications caused in part by increasing CO₂ emissions; 2- the progressive substitution of the current limited carbon resources (coal, petroleum, and natural gas) into CO₂. Carbon dioxide is a renewable C1-feedstock; it is environmentally friendly and easily available from decomposition of organic matter or artificially. The concept behind its utilization is the following : the direct energy supply via combustion of fossil energy carriers produces CO₂, which can be converted back into the energy carrier, thereby leading to an artificial carbon cycle. The result would be double : the recycling of CO₂ and the balancing of the anthropogenic emission into the atmosphere. However, the chemistry of CO₂ shows relevant limitations, due the chemical inertness of CO₂ : a systematic use of CO₂ would only be possible if the CO₂ molecule could be catalytically activated. For this reason, the scientific community is dedicating a crescent number of study projects to the resolution of the problem with the aim to develop effective catalytic species for the valorization of CO₂ as well as of other renewable carbon feedstock, such as natural gas and biomasses (starch, lignin, and cellulose).

The classic heterogeneous catalysis fails to convert CO₂ at mild conditions, which is the principal limiting factor for a large-scale plant activity. On the other hand, homogeneous catalysis operates at milder conditions. In terms of energy balance, catalytic performance, reusability, and scale-up perspectives, the most promising transformations of CO₂ in C₁ or higher chemicals with molecular catalysts are: 1- the reduction to CO; 2- the hydrogenation with H₂ to methanol; 3- the formation of carbonates and polycarbonates. The reduction reactions, although particularly attractive, are not efficient enough and involve hydrogen, an expensive reactant. On the other hand, the synthesis of carbonates and polycarbonates via CO₂ and epoxides is an established procedure supported by the utilization of high-performance metal catalysts. In the field of the molecular catalysts, metal-free catalytic species find a progressively important position. Although they were not so common and explored, the application of metal-free catalysis – i.e., organocatalysts and Lewis pairs based catalysts – would easily out compete metal catalysts in price, stability, and remarkably, green accessibility since heavy metal waste or complicated recovery would be avoided. In the last years, many efforts were produced to define effective routes for the conversion of CO₂ to usable starting materials for further transformations utilizing metal-free catalysts but the accomplishments have been below a feasible real-world day-to-day process to date. Reliable results in development of eco-friendly species for applications in the aforementioned field will strongly contribute in solving urgent problems concerning energy and sustainability themes.