Graphical abstract Ru3(CO)12 has been shown to catalyse the coupling of silanes with thiols, alcohols and amines with TON and TOF up to 200 and 50 h−1. A ruthenium dimer [Ru(CO)4(SiEt3)]2 is believed to be a key intermediate in the process. Highlights ► Si–S, Si–N and Si–O coupling has been catalysed by Ru3(CO)12. ► Ru2(CO)8(SiEt3)2 and H2Ru3(CO)10 have been detected in the catalytic mixture. ► A mechanism involving Ru2(CO)8(SiEt3)2 has been proposed.