Complexes [PhBP3]RuH(eta(3)-H2SiRR) (RR' = Me,Ph, la; RR' = Ph-2, lb; RR' = Et-2, 1c) react with XyINC to form carbene complexes [PhBP3]Ru(H)=[C(H)(N(Xyl) (eta(2) - H-SiRR'))] (2a-c; previously reported for 2a,b). Reactions of la-c with XylNC were further investigated to assess how metal complexes with multiple M-H-Si bonds can mediate transfotinations of unsaturated substrates. Complex 2a eliminates an N-methylsilacycloindoline product (3a) that results from hydrosilylation, hydrogenation, and benzylic C-H activation of XylNC. Turnover was achieved in a pseudocatalytic manner by careful control of the reaction conditions. Complex lc mediates a catalytic isocyanide reductive coupling to furnish an alkene product (4) in a transformation that has precedent only in stoichiometric processes. The formations of 3a and 4 were investigated with deuterium labeling experiments, KLE and other kinetic studies, and by examining the reactivity of XylNC with an eta(3)-H(2)SiMeMes complex (1d) to form a C-H activated complex (6). Complex 6 serves as a model for an intermediate in the formation of 3a, and MAR investigations at -30 degrees C reveal that 6 forms via a carbene complex (1d) that isomerizes to aminomethyl complex 7d,(These investigations reveal that the formations of 3a and 4 involve multiple 4-, 5-, and 6-coordinate silicon species with 0, 1, 2, or 3 Ru-H-Si bonds. These mechanisms demonstrate exceptionally intricate roles for silicon in transition-metal-catalyzed reactions with a silane reagent.