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The photodissociation processes of acetylene via 9-10 eV two-photon energy levels have been studied by dispersed emission and the two-color photofragment excitation spectrum. Experimental results indicate that two dissociation channels have been detected: most (>90%) excited acetylene molecules undergo sequential bond cleavage to yield vibrationally and rotationally hot $C2\cdot (d3\Pi g,A1\Pi u$) and hydrogen atoms, whereas the remaining fraction of molecules undergoes some geometric rearrangement promptly after the two-photon excitation; in the latter case, subsequent excitation leads to concertive bond ruptures to form $C2\cdot (C1\pi g,A1\Pi g)$ and $H2$. The intermediate state, assigned to be $C2H3$, in the sequential bond breakage has a lifetime $2.5,\pm 0.2\mu s$.