Non-innocent ligands are a special class of redox-active ligands, which can take up or donate electrons to transition metal centers and can mask their oxidation states. The non-innocent ligands can thus play a cooperative role in the reactivity of the complexes. Our group employs non-innocent pyridine, diimine ligands for late transition metal compounds with multiple bonds to main-group elements M=X (N, NR, S). In the lecture, intra- and intermolecular C-H, H-H, Si-H and C-C activation processes will be reported, which were analyzed in detail through mechanistic, spectroscopic and theoretical studies.