The present contribution is focused on the relation preparation – structure – optical properties of hybrid silica and zirconia powders containing Eu(III) complexes: [Eu(ntac)₃][pphendcn] and [Eu(phen)₂](NO₃)₃. Methods for functionalization of silica and zirconia microparticles, based on adsorption of 1,10-phenantroline and [Eu(ntac)₃][pphendcn], and doping with [Eu(phen)₂](NO₃)₃ nanoparticles are proposed to obtain of red emitting hybrid composites with quantum efficiency 20 – 50 %. The optical properties of rare earth ions incorporated in silica and zirconia composites are used to explore the site symmetry (D₂, C_2v or lower) of the Eu³⁺ optical centers in the hybrid composites. Quantum yields of the investigated sol-gel micropowders and quantification of their optical spectra are presented.