The irradiation of N-2-thenoyloxyaryl-4-tert-butylphenoxyacetamides in their molecular film states at 254 nm was found to selectively afford the corresponding photo-Fries rearranged products. This rearrangement reaction was also found to lead to a large increase in the refractive indices of the films, which ranged from 0.021 to 0.035.