ETS-10 is a titanosilicate zeolite, comprising one-dimensional chains of corner linked TiO₆ octahedra surrounded by tetrahedral silicate which give three dimensional pore structures. Each octahedral TiO₆ in the framework carries 2^- negative charges, and electrical balance of the system is preserved by extra-framework cations, which are exchangeable. The one-dimensional TiO₆ chains have drawn particular attention, since they can be considered as nanowire semiconductors within an insulating siliceous sheath. Our interest is in developing these materials as photocatalysts. This paper will describe our use of infrared and Raman spectroscopies to study the structure and photoreactivity of ETS-10. In-situ infrared spectroscopy has been used to study the adsorbed species produced when ETS-10 is irradiated in the presence of ethylene or ethylene plus oxygen. The reactivity of ETS-10 is found to depend strongly on the presence of defects in the structure. The presence of defects also profoundly modifies the Raman spectrum of ETS-10. As-synthesised well crystalline samples of ETS-10 give a sharp and intense Raman band at 724 cm^-1, assigned to coupled Ti-O-Ti vibrations in the TiO₆ chains. The shape and frequency of the peak is related to the crystallinity of the material. Ion exchange causes marked changes in the Raman spectra; the origins of these changes will be discussed.