In the structure of the first bis-adduct of 2,5-bis[3-(tert-butylaminoxyl)phenyl]-1,1-dimethyl-3,4-diphenylsilole with bis(hexafluoroacetylacetonato)manganese(II), [Mn(C5HF6O2)2(C38H42N2O2Si)2], the Mn atom lies on a crystallographic inversion centre and is bound to two chelating hexafluoroacetylacetonate ligands and two monodentate nitroxide groups in a distorted octahedral configuration. The silole ligands present a propeller-like arrangement of the benzene rings around the Si-containing five-membered ring. The dihedral angles between the complexed nitroxides and the benzene rings to which they are bound are smaller than those found in the free ligand.