Overall, while it is well known that ruthenium catalysts bearing NHC ligands with low steric demand are more fragile, which impairs their productivity, we showed here that the adjunction of a second decker of aromatic groups in the NHC scaffold is a viable and promising strategy to access very stable and efficient olefin metathesis catalysts. Because the formation of sterically hindered olefins has always been the Achilles' heel of the ruthenium-catalysed metathesis, this special trait exhibited by the newly obtained complexes appears of paramount importance. We believe that the present report will open up new possibilities for further developments of olefin metathesis catalysts and will significantly extend applications of this transformation in natural product synthesis and medicinal chemistry.