The reactions of 3,4-benzo-1,1,2,2-tetra(isopropyl)-1,2-disilacyclobut-3-ene ( 2) with acetylene, phenylacetylene, 1-hexyne, and o-tolylacetylene in the presence of tetrakis(triphenylphosphine)palladium gave the respective 5,6-benzo-1,4-disilacyclohexa-2,5-dienes 3–6. Similar reactions of 2 with mesitylacetylene, trimethylsilylacetylene, and dimethylphenylsilylacetylene afforded 1-alkynyl(diisopropylsilyl)-2-(diisopropylsilyl)benzenes 7–9 arising from sp-hybridized CH bond activation of acetylenes. The reactions of 3,4-benzo-1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene with mesitylacetylene, trimethylsilylacetylene, and dimethylphenylsilylacetylene produced 5,6-benzo-1,4-disilacyclohexa-2,5-dienes 10–12 as the sole product. The stoichiometric reaction of 2 with tetrakis(triphenylphosphine)palladium gave a yield of 3,4-benzo-2,2,5,5-tetra(isopropyl)-1-pallada-2,5-disilacyclopent-3-ene ( A), arising from insertion of a palladium species into a silicon-silicon bond in 2.