Abstract: Laser flash photolysis of various organosilicon compounds such as aryl-, vinyl- and alkynyldisilanes, silacyclobutanes and silacyclobutenes, and a-silylketenes and -diazomethanes leads to the formation of reactive silenes which can be detected directly in solution, allowing detailed studies of the kinetics and mechanisms of their reactions with nucleophiles. Over thirty transient silenes have now been studied by these methods, providing the opportunity to systematically assess the effects of substituents at silicon and carbon on the reactivity of the Si=C bond.