What is the most significant result of this study?We have demonstrated that functionalization of the corners of cage germanoxanes with silyl groups was successful by using a combination of chlorosilane and silazane to minimize the generation of hydrogen chloride. This finding opens the door for applications of the cage germanoxane in various fields. In this study,w e have established an effective method for the functionalization of a cubic cage germanoxane containing af luoride ion inside the cage. The cage germanoxane is expected to show various unique properties owing to its charge and rigid structure. For the molecular design of cage germanoxane as versatile building blocks, the introduction of organic functional groups onto the corner Ge atoms is essential.What was the inspiration for this cover design?We represented ac age germanoxane as ab irdcage and af luoride ion as ab ird caught in the cage. Silyl groups are represented as yellow birds catching the birdcage and flying up to the sky,w hich expresses successful silylation of the cage germanoxane and a bright future for cage germanoxane.What was the biggest surprise (on the way to the results presented in this paper)?When we started this study,w ea ssumed that silylation of germanoxane could proceed without any problem. However,t he cage was decomposed when chlorosilane was used as as ilylating agent, and the reaction did not proceed when silazane was used. Successful silylation using ac ombination of chlorosilane and silazane surprised us and gave atremendous boost to our research.Invited for the cover of this issue is the group of Atsushi Shimojima and Kazuyuki Kuroda at Waseda University.T he image depicts the functionalization of ac ubic cage germanoxane( birdcage) containing af luoridei on (blueb ird) inside the cage. Read the full text of the article at

Two types of cage-type oligosiloxanes with double-three ring (D3R) structures are modified with dimethylsilanol groups to form crystalline supramolecular assemblies.

Invited for the cover of this issue is the group of Atsushi Shimojima and Kazuyuki Kuroda at Waseda University. The image depicts the functionalization of a cubic cage germanoxane (birdcage) containing a fluoride ion (blue bird) inside the cage. Read the full text of the article at 10.1002/chem.201900439.

A double‐four ring cage germanoxane, containing a fluoride ion, was successfully silylated by the combination of chlorosilanes and silazanes. The solubility and reactivity of the cage were significantly increased, allowing further reaction, which provides a pathway toward rational design of cages as nano building blocks with intrinsic charges. More information can be found in the Full Paper by A. Shimojima, K. Kuroda, et al. on page 7860.