- The commercially available catalyst cis-Caz-1 is extremely robust, especially when reactions are performed in an atmosphere of air. This phosphite-containing ruthenium complex only shows olefin metathesis activity at high temperatures. Herein, we report photoactivation of cis-Caz-1 at room temperature with UVA light. Thus, a wide variety of olefin metathesis reactions was performed under mild conditions with good yields. In addition, we report the synthesis, characterization, and catalytic activity of a phosphite-chelated ruthenium benzylidene complex, cis-PhosRu-1, which can be efficiently activated either by irradiation with visible light (λ = 405 nm) or by heat.