Easy feasible and effective methods of the synthesis of silsesquioxanes [equations (1) -(6)] were elaborated. Twelve types of these products with various organic substituents: the same (Table 1 and 3) or different ones (Table 2 and 3) at silicon atom were obtained. Alkyl, phenyl, vinyl or carbofunctional groups act as substituents. Silsesquioxanes obtained were characterized using the following methods: FT-IR (Fig. 2), H NMR (Fig. 3), 2 9 Si NMR, gel permeation chromatography, mass spectrometry (Fig. 4) and scanning electron microscopy (Fig. 5). Molecular weights of liquid silsesquioxanes (soluble in organic solvents) were usually in the range 500-1500 g/mol. Some samples of poly(methyl silsesquioxanes) consisted of spherical particles of dimensions 50-150 nm. It has been found from the results of structural investigations of the products that the structures of closed cage type - mainly T 8 (Fig. 1) are formed.