Distribution of organic guest molecules within Na Y zeolites has been examined utilizing aromatic probe molecules such as pyrene, naphthalene and phenanthrene, and dyes such as thionin as photophysical probes. Results have been analyzed on the basis of three parameters, guest occupancy, families of sites and distribution of sites within a family. Distribution of guests, on all three counts, within zeolites has been shown to be non-uniform. Co-adsorbed molecules such as water and organic solvents, temperature and the nature of aromatics influence significantly the guest distribution within zeolites.