Reaction of azasilaboroles I (R = Me, CMe:CH2) with hydroxy compds. is reported. Thus, reaction of I (R = Me) with R1OH (R1 = Me, Et, Ph) gave R1OSiMe2CMe:CEtB(OR)Et, whereas with dihydroxycompds., HOXOH [X = CH2CH2, CHMeCH2, CHMeCHMe, CMe2CMe2, (CH2)3, (CH2)4], cyclic ring compds. e.g. II are obtained. The reaction of I (R = Me) with arom. dihydroxy compds. catechol, resorcinol, 2,3-dihydroxynaphthalene, and 1,8-dihydroxynaphthalone gave mainly BCvinyl fission products 2,5-dihydro-1,2,3-dioxaboroles along with boron free compds. and their dyotropic rearranged isomers. The crystal structure of II was detd. by x-ray diffraction.