Abstract: The disclosure provides Group 6 complexes, which, in some embodiments, are useful for catalyzing olefin metathesis reactions. In some embodiments, the compounds are compounds of the following formula: wherein: M is a Group 6 metal atom; X is an oxygen atom, ?N—R5, ?N—N(R5)(R5?) or ?N—O—R5, R5 and R5? independently being various substituents, such as aryl or heteroaryl, each optionally substituted; n is 0 or 1; Rz is a neutral ligand; R1 is hydrogen or an organic substituent; R2 is an aryl or heteroaryl group, each optionally substituted; R3 is an anionic ligand; and R4 is an anionic ligand, such as a pyrrolide, a pyrazolide, an imidazolide, an indolide, an azaindolide, or an indazolide, each optionally substituted.