Photolysis of the cyclic acylsilane 1,1-diphenyl-l-silacyclohexanone-2 yields 1,1-diphenyl-1-silacyclopentane and two dimeric products whose structures were established by chemical and spectroscopic methods. A mechanism involving a siloxycarbene intermediate which is trapped by a second acylsilane molecule, is proposed for the formation of the dimers.