In the mid-1990s, the first examples of complexes containing triple bonds between transition metals and heavier analogues of the carbon as well as the nitrogen groups were reported, thus signaling the beginning of a new era in organometallic chemistry. Since then the progress in this field has been tremendous, with a large number of representative complexes being isolated and characterized. This review highlights the astonishing development of the chemistry of complexes containing triple bonds between transition metals and the heavier elements of groups 14 and 15 since its birth. The synthesis and the structural and spectroscopic features of these compounds are comprehensively discussed. Furthermore, the elucidation of their bonding modes by quantum-chemical methods as well as the relation between the reactivities of these complexes and their electronic structures are presented.