Research in the Grubbs group has centered on the development and application of a suite of highly active, selective, and bench stable ruthenium alkylidene complexes capable of catalyzing versatile olefin metatheses. Most notably, access to monodisperse polymers and macrocyclic/linear small molecules has been enabled through the use of these precatalysts. The ligands on ruthenium include, but are not limited to, neutral phosphines, N-heterocyclic carbenes, and pyridyl moieties, which allow for manipulations of initiation and/or propagation activity, stability, and selectivity. Similar accomplishments have been achieved with anionic ligand variations. Traditionally, olefin metathesis predominantly forms the thermodynamically favored (E)-olefin. Recent developments, however, which make use of cyclometallated N-heterocyclic carbene ruthenium alkylidene complexes, have unveiled a catalyst that forms (Z)-olefins almost exclusively. Advances in metathesis catalysts in the Grubbs group have had ubiquitous applications in the fields of energy, materials, pharmaceuticals, and natural product total synthesis.