The Friedel-Crafts acylation of octaphenylsilsesquioxane (T8Ph8) (1) with Cl(2)CHOCJ(3) or CH3COCl at low temperature followed by subsequent hydrolysis provided the octakis(m-acylphenyl)octasilsesquioxanes (T-8(C6H4R-m)(8)), R = CHO (2a) and R = COCH3 (2b) in high yields The remarkable meta-selectivity of 2a and 2b in more than 99:1 and 93 7 meta I pat a ratios was confirmed by H-1 NMR and X-ray analyses, and further elucidated via theoretical calculations