Cooperative E-H (E = B, Si) bond activations employing κ2-N,S-chelated ruthenium borate species, [PPh3κ2-N,S-(NS2C7H4)Ruκ3-H,S,S′-H2B(NC7H4S2)2], (1) are established. Treatment of 1 with BH3·SMe2 yielded the six-membered ruthenaheterocycle [PPh3κ2-S,H-(BH3NS2C7H4)Ruκ3-H,S,S'-H2B(C7H4NS2)2] (2) formed by a hemilabile ring opening of a Ru-N bond and capturing of a BH3 unit coordinated in an "end-on"fashion. On the other hand, the bulky borane H2BMes shows different reactivity with 1 that led to the formation of the two dihydroborate complexes [κ3-S,H,H-(NBH2Mes)(S2C7H4)Ruκ3-H,S,S'-H2B(C7H4NS2)2] (3) and [PPh3κ3-S,H,H-(NBH2Mes)(S2C7H4)Ru(κ2-N,S-C7H4NS2)] (4), in which H2BMes has been inserted into the Ru-N bond of the initial κ2-N,S-chelated ligand. In an attempt to directly activate hydrosilanes by 1, reactions were carried out with H2SiPh2 that yielded two isomeric five-membered ruthenium silyl complexes, namely [PPh3κ2-S,Si-(NSiPh2)(S2C7H4)Ruκ3-H,S,S'-H2B(C7H4NS2)2] (5a,b), and the hydridotrisilyl complex [Ru(H)κ2-S,Si-(SiPh2NC7H4S23] (6). These complexes were generated by Si-H bond activation with the release of H2 and the formation of N-Si and Ru-Si bonds. When the reaction of 1 was carried out in the presence of PhSiH3, the reaction only produced the analogous complexes [PPh3κ2-S,Si-(NSiPhH)(S2C7H4)Ruκ3-H,S,S'-H2B(C7H4NS2)2] (5a′,b′). Density functional theory (DFT) calculations have been used to probe the bonding modes of boranes/silane with the ruthenium center. © 2021 American Chemical Society. All rights reserved.