Carbenes and nitrenes are versatile reactive intermediates that find widespread application in organic synthesis. Their high reactivity, however, often necessitates the use of metal complexes for stabilization of such species. [1,2] Herein, we describe our recent approaches towards photochemical and photocatalytic carbene and nitrene transfer reactions. Strategies in accessing either singlet or triplet carbenes will be discussed and their applications in synthesis methodology will be presented.[3,4] We commence with a discussion of nitrene intermediates and how these can be accessed under visible light irradiation without the need of conventional metal catalysts. We describe strategies, how the access of nitrene intermediates can be manipulated by single electron transfer reactions or direct photoexcitation.[5] We conclude with a discussion of a collaborative approach towards drug discovery, where fundamental discoveries can be translated into new drugs and medicines.[6]