Three 1,2-diaryltetramethyldisilanes X5C6-(SiMe2)2-C6X5 with two C6H5, C6F5 or C6Cl5 groups were studied concerning the im-por-tan-ce of London dispersion driven interactions between their aryl groups. They were prepared from 1,2-di-chlo-rotetra-methyl-disi-la-ne by salt elimination. Their structures were determi-ned in the solid state by X-ray diffraction and for free molecules by gas elec-tron-diffraction. The solid-state struc-tures of the fluori-nated and chlo-rinated derivatives are domi-na-ted by aryl-aryl inter-actions. Unex-pectedly, Cl5C6-(SiMe2)2-C6Cl5 exists exclusive-ly as eclipsed syn-conformer in the gas phase with strongly distor-ted Si-C6Cl5 units due to strong intramo-le-cular interactions. In contrast, F5C6-(SiMe2)2-C6F5 reveals wea-ker inter-actions. The contributions to the total interaction energy was analyzed by SAPT calculations. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.