In this Atazanavir work we focus our attention on preparation and optical characterization of novel type of POSS family compounds possessing photochromic properties due to incorporation of photoactive substituents. As photoactive R-group we employed alkyl chain with incorporated azo-group. The synthesis route of two different monoesters of BAFKP and BAFKU has been already reported in Ref. . Both compounds were found to be thermotropic liquid crystals with characteristic temperatures of nematic or smectic phase existence: TC–N = 59.0 °C, TN–I = 64.0 °C for BAFKP and TC–SmC = 54.5 °C, TSmC–I = 65.5 °C for BAFKU. Their POSS derivatives were synthesized by hydrosilylation reaction of respective BAFKP and BAFKU monoesters with octakis(hydridodimethylsiloxy) octasilsesquioxane. The process was carried out in the presence of Karstedt catalyst and toluene as a solvent. In Fig. 1 we show the scheme of heterotrophic reaction and final products .