**4. Conclusions**

The development of new methodologies to perform the α-functionalization of imine building blocks has proven to be a subject of intense research during the past decade, as numerous approaches featuring outstanding versatility have surfaced in the context of visible light photoredox catalysis. Most importantly, the complimentary nature to the different photocatalytic strategies employed in imine chemistry has provided immense flexibility, since the imine reagen<sup>t</sup> can now be used as both an electrophile and, strikingly, a nucleophile. This multifaceted behavior has delivered a wide array of racemic transformations in this area. However, asymmetric functionalization of the C=N moiety has remained a grea<sup>t</sup> challenge in photoredox catalysis. Nevertheless, brilliant activation strategies have been deployed to achieve stereoselectivity, although an increase in generality and modularity can be expected as the field continues to grow.

**Author Contributions:** Conceptualization, A.F.G.-C. and M.C.M.; literature search, A.F.G.-C. and M.C.M.; writing—original draft preparation, A.F.G.-C.; writing—review and editing, A.F.G.-C., M.C.M., and J.A.; supervision, M.C.M. and J.A.; project administration, M.C.M. and J.A.; funding acquisition, M.C.M. and J.A. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the European Research Council, gran<sup>t</sup> number 647550; the Spanish Government, gran<sup>t</sup> number RTI2018-095038-B-I00; the "Comunidad de Madrid" and European Structural Funds, gran<sup>t</sup> number S2018/NMT-4367.

**Conflicts of Interest:** The authors declare no conflict of interest.
