A ruthenium-catalyzedswitchableN–H/C–Halkenylation reaction of 6-phenyl-(dihydro)pyridazin-3(2H)-ones triggered by a nitrogen/oxygen atmosphere was developed. To achieve switchable modification of the two important sites of the widely used pharmacophore, a simple and efficient procedure containing two optimized ruthenium catalytic systems was utilized, which afforded excellent activity, high selectivity