The photolyses of benzyl p-methylphenylacetate (BCO2A), 1-naphthyl phenylacetate (ACO2N), p-methylbenzyl benzyl sulfone (ASO2B) and 1-naphthyl benzyl sulfone (ASO2N) were carried out on the pentasil and faujasite zeolites. The product distribution, in terms of the cage effect, was extremely sensitive to zeolite structure. Photolyses of BCO2A and ASO2B adsorbed on NaZSM-5 produce AB as the main product. In contrast, photoirradiation of ACO2N and ASO2N adsorbed on NaZSM-5 only gives AA and NN as the products, and the cage effect is essentially-100%. All the four substrates adsorbed on NaY zeolite show higher cage effects in the photolysed products compared with those in homogeneous solutions. All the observations are interpreted by consideration of size and shape sorption selectivity of the substrate molecules on the zeolite surface and restriction on diffusional motion of the photogenerated radicals imposed by zeolite surface. Application of a weak external magnetic field in the photolysis decreases the cage effects in all cases, which demonstrates that the reactive states for the photocleavage reaction of the esters and sulfones mainly involve triplet excited states.