New methoxylated oligosilyl-substituted metallocenes were synthesized by the reaction of two oligosilanides with different metallocene dichlorides (M = Ti, Zr, and Hf). The first investigated tris(trimethoxysilyl)silanide [(MeO) 3 Si] 3 SiK ( 1 ) underwent a selective monosubstitution to the respective oligosilyl-decorated metallocenes [(MeO) 3 Si] 3 SiMClCp 2 ( 2 – 4 ). Surprisingly, the attempted disilylation with this silanide was not possible. However, in the case of titanocene dichloride, a stable radical [(MeO) 3 Si] 3 SiTiCp 2 ( 5 ) was formed. The unsuccessful isolation of bisilylated metallocenes encouraged us to investigate the reactivity of another silanide. Therefore, we synthesized a hitherto unknown disilanide K[(MeO) 3 Si] 2 Si(SiMe 2 ) 2 Si[(MeO) 3 Si] 2 K ( 8 ), which was accessible in good yields. The reaction of compound 8 and different metallocene dichlorides (M = Ti, Zr, and Hf) gave rise to the formation of heterocyclic compounds 9 – 11 in good yields.

Organic solar cells have been continuously studied and developed through the last decades. A major step in their development was the introduction of fused‐ring non‐fullerene electron acceptors. Yet, beside their high efficiency, they suffer from complex synthesis and stability issues. Perylene‐based non‐fullerene acceptors, in contrast, can be prepared in only a few synthesis steps and display good photochemical and thermal stability. Herein, we introduce four monomeric perylene diimide acceptors obtained in a three‐step synthesis. In these molecules, the semi‐metals silicon and germanium were added in the bay position, on one or both sides of the molecules, resulting in asymmetric and symmetric compounds with a red‐shifted absorption compared to non‐substituted perylene diimide. Introducing two germanium atoms improved the crystallinity and charge carrier mobility in the blend with the conjugated polymer PM6. In addition, charge carrier separation is significantly influenced by the high crystallinity of this blend, as shown by transient absorption spectroscopy. As a result, the solar cells reached a power conversion efficiency of 5.38%, which is one of the highest efficiencies of monomeric perylene diimide‐based solar cells recorded to date.