Reaction of 1H-cyclopropa [b]naphthalene (1a) or 1H-cyclopropa[b]anthracene (10a) with tris(acetonitrile)tricarbonylchromium affords cyclobutanaphthalenone and cyclobutaanthracenone 2 and 11, respectively. In contrast, the bis-silylated Cycloproparenes 1b and 10b undergo complexation at the terminal benzene ring and lead to the arene-tricarbonylchromium complexes 4b and 12, respectively. Desifylation of 4b to 4a is effected by t-BuOK.