New strained bicyclic compounds were formed by the reaction of tetrakis[di-tert-butyl(methyl)silyl]-1 -disilagermirene 1 with benzaldehyde, involving cycloaddition following the rearrangement and insertion pathways. Reaction of 1 with PhCHO gave three different products: two mono-adducts 2, 3 and one bis-adduct 4, depending on the ratio of the reagents and the reaction conditions.