Photochemical generation of dibeniOsilacyclohept-4-yne 3 from the corresponding, cydopropenone 1 and its copper-free click reactions are reported. Steady-state irradiation, kinetic, and- transient absorption spectroscopy studies revealed that strained alkyne 3 is rapidly (<5 ns) and efficiently (Phi = 0.58-0.71) photoreleased from 1 and undergoes remarkably fast, selective, and high-yielding 1,3-dipolar cycloaddition with benzyl azide (similar to 20 M-1 s(-1)) or [4 + 2] inverse electron-demand Diels Alder reaction with 1,2,4,5-tetrazines (similar to 260 M-1 s(-1)) in both methanol and acetonitrile.