A Roadmap Towards Visible Light Mediated Electron Transfer Chemistry with Iridium(III) Complexes

Abstract Photo‐induced electron transfer chemistry between molecules is a central theme in several fields including biology, physics and chemistry. Specifically, in photoredox catalysis, greater use has been made of iridium(III) complexes as they exhibit ground‐ and excited‐state redox potentials that span a very large range. Unfortunately, most of these complexes suffer from limited visible light absorption properties. This concept article highlights recent developments in the synthesis of iridium(III) complexes with increased visible light absorption properties and their use as candidates for visible light driven redox catalysis. Fundamental tools are provided to enable the independent tuning of the HOMO and LUMO energy levels. Recent examples are given with the hope that this concept article will foster further developments of iridium(III)‐based sensitizers for visible light driven reactivity.