The catalytic effect obtained by opening the coordination sphere of the organoactinide complex is presented. Replacing the pentamethylcyclopentadienyl ligand in Cp*ThCl (Cp*5C Me) by the bridge ligation [Me SiCp99]22 2[Li]1 (Cp05C Me) affords the 22552254 synthesis of ansa-Me SiCp99ThCl, which reacts with two equiv of BuLi affording the corresponding dibutyl complex ansa-222Me SiCp99Th0Bu. This latter complex was found to be an active catalyst for the dimerization of terminal alkynes, and in the222hydrosilylation of terminal alkynes with PhSiH. In both processes a large chemoselectivity and regioselectivity are achieved due to the3hindered equatorial plane, attributed to the disposition of the methyl groups in the bridge ligation, forcing the incoming substrates to react with a specific regiochemistry.