Facile syntheses of three new incompletely condensed polyhedral oligosilsesquioxanes are reported. Trisilanols [(c-C 5 H 9 ) 7 Si 7 O 9 (OH) 3 and [(c-C 7 H 13 ) 7 Si 7 O 9 (OH) 3 ] are prepared by the hydrolytic condensation reactions of c-C 5 H 9 SiCl 3 and c-C 7 H 13 SiCl 3 in refluxing aqueous acetone. The hydrolytic condensation of c-C 7 H 13 SiCl 3 at 25°C also affords tetrasilanol [(c-C 7 H 13 ) 6 Si 6 O 7 (OH) 4 ]. These straightforward syntheses produce multigram quantities of incompletely condensed silsesquioxanes within a few days