Hypervalent iodine reagents have a prominent role in organic synthesis, but there is only a slowly emerging chemistry employing these reagents for transition metal organometallic synthesis, despite the early promising results reported in the 1960s, and extensive reports of the application of diorganoiodine(III) reagents in organic synthesis involving metal centres. This review summarises the fundamental aspects of mechanisms proposed for organic chemistry applications, reviews representative reports in organometallic chemistry with this perspective, and highlights the potential for further developments in the field.