With the development of the synthesis of compounds with heavier group 14 elements, their applications in catalysis was the next logical target. The past few years have witnessed tremendous headway in the field of catalysis by compounds with heavier group 14 elements, which can be seen from the exponential number of recent publications in high-impact journals. In this article, recent developments in the utilization of well-defined germylenes in catalysis will be presented, which has been the starting point for rich and exciting chemistry, with the prospect of numerous remarkable contributions from synthetic, theoretical, and materials chemistry. Emphasis has been given in elucidating the mechanism of the germylene-catalyzed reactions.