Thermal annealing induced formation of nanocrystalline Zinc silicate (α-Zn 2SiO 4) at the interface of ZnO–porous silicon (PSi) nanocomposites is reported. The PSi templates were formed by electrochemical anodization of p-type (100) Si and ZnO crystallites were deposited on the PSi surface by a Sol–gel spin coating process. The formation of α-Zn 2SiO 4 is confirmed by glancing angle X-ray diffraction and Fourier transform infrared spectroscopy studies. The presence of intense yellow-green emission also confirms the formation of α-Zn 2SiO 4. The mechanism of silicate phase formation at the ZnO–PSi interface and the origin of various photoluminescence (PL) bands are discussed in view of its potential applications in advanced optoelectronic devices.