Chemical photocatalysis using visible light Burkhard König University of Regensburg, Department of Chemistry and Pharmacy D-93040 Regensburg, GERMANY The use of visible light for organic synthesis is a very old idea: More than 100 years ago the Italian chemist Giacomo Ciamician discovered and promoted the field. Recently, photoredox chemistry mediated by metal complexes, such as ruthenium-trisbipyridine, or organic dyes, such as eosin, gained enormous interest for applications in organic synthesis. We present some of the recent results[1] using photoredox catalysis (PRC) with visible light from our laboratory including photooxidations, oxidative C-C bond formation and photo-Meerwein arylation reactions. [1] (a) D. P. Hari, B. König, Chem. Commun. 2014, 50, 6688 - 6699; (b) D. P. Hari, T. Hering, B. König, Angew. Chem. Int. Ed. 2014, 53, 725 - 728; (c) P. Schroll, C. Fehl, S. Dankesreiter, B. König, Org. Biomol. Chem. 2013, 11, 6510 - 6514; (d) D. P. Hari, B. König, Angew. Chem. Int. Ed. 2013, 52, 4734 -4743; (e) T. Hering, D. P. Hari, B. König, J. Org. Chem., 2012, 77, 10347-10352; (f) D. P. Hari, T. Hering, B. König, Org. Lett. 2012, 14, 5334 - 5337; (g) P. Schroll, D. P. Hari, B. König, ChemistryOpen 2012, 1, 130 -133; (h) D. P. Hari, P. Schroll, B. König, J. Am. Chem. Soc. 2012, 134, 2958 - 2961; (i) M. Cherevatskaya, M. Neumann, S. Füldner, C. Harlander, S. Kümmel, S. Dankesreiter, A. Pfitzner, K. Zeitler, B. König, Angew. Chem. Int. Ed. 2012, 51, 4062 - 4066