Over the last few years our group has been strongly involved in the study of the chemistry of oligosilanes. In particular, the development of a convenient synthetic access to structurally diverse oligosilanyl anions 6 allowed the preparation of a huge variety of previously unknown small polysilanes. Some 40 years ago Ishikawa and Kumada discovered the AlCl3-catalyzed rearrangement of linear methylated oligosilanes to branched isomers. This chemistry can be considered to be complementary to our oligosilanyl anion chemistry, as it produces the strongly branched oligosilanes that are required as precursors for effectively stabilized oligosilanyl anions. We became aware of this potential during the synthesis of an allsilicon analogue of the adamantane structure. In a subsequent study we investigated AlCl3-catalyzed rearrangement reactions of already branched cyclosilanes. One of the main conclusions we could draw from this work was that these rearrangement reactions always lead to substituted cyclopentasilanes. More recently, we showed that the introduction of trimethylgermyl groups into oligosilanes followed by AlCl3-catalyzed rearrangement exclusively led to the formation of isomers with germanium atoms possessing the highest possible silylation degree. In the course of this study a computational investigation of the reaction mechanism demonstrated its similarity to the well-known Wagner Meerwein reaction: starting with the abstraction of a methyl group from the oligosilane, a silylium ion forms, which undergoes a series of 1,2-methyl and -silyl shifts until the most stable ion is obtained. Eventually remethylation of the ion concludes the rearrangement process.