: Transition metal-catalyzed C–H bond activation has evolved exponentially in recent years and has found a growing number of applications in practical synthesis. Major advances in this field have been made with catalysts based on rare transition metals. On the other hand, increasing interest in sustainable catalysis has recently stimulated chemists into the development of alternative and more affordable catalysts based on earth-abundant transition metals. Among such metals, cobalt appears particularly attractive in light of the diversity of C–H functionalization reactions catalyzed by its heavier congener, rhodium, in both low- and high-valent states, as well as the similar reactivity patterns of these metals in a variety of homogeneous catalytic reactions. In this talk, our recent studies on the development and application of C–C bond-forming reactions via low-valent cobalt-catalyzed C–H activation will be discussed.