The synthesis of nanosized organic benzil (C6H5CO)2crystals within the mesoporous SiO2host matrix was investigated via X-ray diffraction, transmission electron microscopy, Raman spectroscopy, andab initiolattice dynamics analysis. Combining these methods, we have proved that the main structural properties of benzil nanocrystals embedded into SiO2host membranes with pore diameters of 6.0, 7.8, 9.4, and 13.0 nm are preserved compared to a bulk benzil crystal. Space confinement has an insignificant impact on the lattice vibrational properties of benzil crystals implanted into the host matrices. Theab initiolattice dynamics calculation of the phonon spectrum in the Brillouin zone center shows the mechanical and dynamical stability of benzil lattice, revealing very low optical frequency of 11 cm−1at pointΓ.