Abstract: Iridium complexes have played a leading role in the organometallic chemistry of alkanes and unreactive C-H bonds since the inception of the field 30 years ago. We have found that ​“PCP”-pincer-ligated iridium complexes are particularly effective for the dehydrogenation of alkanes and have incorporated this reaction into tandem systems for several catalytic transformations based on dehydrogenation. A closely related class of reactions that we are exploring is dehydrogenative coupling. More recently we have turned attention to iridium Phebox complexes. Although the (PCP)Ir and (Phebox)Ir units are formally isoelectronic, the former operates via C-H activation by Ir(I) while the latter effects dehydrogenation via Ir(III) (as an acetate complex) and possibly Ir(V) intermediates. Such a high-oxidation-state catalytic cycle offers advantages for many potential applications of dehydrogenation. In parallel, however, we find that the low-oxidation-state (+I) chemistry of (Phebox)Ir offers its own novel hydrocarbon chemistry.