The past decade has witnessed increasing activity in photochemistry within zeolites. This article critically reviews the topics of such activities and provides some comments for future studies. Particular emphasis is placed on transient spectroscopic studies, which have shown to be a powerful technique for mechanistic investigations in solid systems. As a host material for organic species, zeolites are another promising candidate for modifying the photophysics and photochemistry of a given species. Besides, photochemical reactions can be pursued in zeolites and provide product distributions considerably different from those in solutions. Accordingly, photochemistry has enjoyed a great benefit from zeolite materials and zeolite science. In return, photochemical techniques can provide pieces of useful information on the fundamental issues of zeolite science such as adsorption and diffusion of molecules within the zeolite. Thus, we can expect further development in this area if this cooperative relationship continues. In this article, we mainly describe mechanistic aspect of photochemical reactions. Issues associated with experimental techniques are also reviewed.