Heterogeneous catalysis, a field important industrially and scientifically, is increasingly seeking and refining strategies to render itself more predictable. The main issue is due to the nature and the population of catalytically active sites. Their number is generally very low, their “acid strengths” or “redox properties” is not homogeneous, and the material may display related yet inactive sites on the same material. In many heterogeneous catalysts, the discovery of a structure-activity relationship is at best challenging. One possible solution passes by generating single-site catalysts in which most of, if not all, the sites are structurally identical. Within this context and using the right tools, the catalyst structure can be well-defined, that is elucidated to reach a molecular understanding. It is then feasible to understand structure-activity relationship and to develop predictable heterogeneous catalysis. Single-site well-defined heterogeneous catalysts can be prepared using Surface Organometallic Chemistry. This approach operates by reacting organometallic compounds with surfaces of highly divided oxides (or of metals nano particles). This strategy has a solid track record to reveal structure-activity relationship to the extent that it is becoming now quite predictable. Almost all the elements of the periodical table have been grafted on surfaces of oxides (from simple oxides such as silica or alumina to more sophisticated materials regarding composition or porosity). 

Considering catalytic hydrocarbon transformations, heterogeneous catalysis outcome may now be predicted based on existing mechanistic proposition and the rules of molecular chemistry (organometallic, organic, supramolecular) associated to concepts of surface sciences. A thorough characterization of the grafted metal centers must be carried out using tools spanning from molecular organometallic or surface chemistry. By selecting metal and its ligand set (or support taken as a X, L, Z ligands in the Green