In this work, efficient trans reversible arrow cis photo-switchings of 4-(4-cyano)styrylpyridine (stpyCN) coordinated to organometallic bipyridyl tricarbonyl rhenium(I) complexes, fac-[Re(CO)(3)(NN)(trans-stpyCN)](+), where NN = 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (dmb), are described. For both complexes, the true trans-to-cis quantum yields determined by H-1 NMR spectroscopy are similar at 313, 334, and 365 nm irradiations (Phi(true(313-365nm))(trans ->)(cis)similar to 0.45), with a small decrease at 404 nm (Phi(true(404nm))(trans ->)(cis)similar to 0.37). The investigated complexes also exhibit significant quantum yields for the reversible cis-to-trans photoreactions (Phi((255nm))(cis -> trans) = 0.22). The luminescent properties of these complexes were also analyzed in different media to elucidate a key role of the (ILstpyCN)-I-3 state in photophysical and photochemical processes, giving new insights on their intriguing photobehavior.