CdS and ZnS particles were synthesised inside some synthetic mordenite and natural clinoptilolite and monocrystalline laumontite by treating the calcined Cd²⁺ and Zn²⁺ ion exchanged forms with 1 molar solution Na₂S. The photoluminescence emission spectra (λ= 337 nm) were recorded at 293 and 77 K. Stokes-shifted luminescence suggests that ZnS and CdS exists mostly as well-defined aggregates. The electrical measurements were made as a function of temperature and evidenced some changes in the electrical conductivity and in the thermal activation energy of zeolites having semiconductor nanocrystallites in their channels.