Since its discovery in 1966 the photorefractive effect, i.e. the change of the refractive index upon illumination with light, was extensively studied in various materials and turned out to play a key role in modern optical technologies like photonics. The topic of this article is to consider substances that change their refractive index for neutrons when irradiated with light. In analogy to light optics we call them photo-neutronrefractive. After a short introduction to the relevant concepts of neutron optics two materials exhibiting that effect, a photopolymer and an electrooptic crystal, are presented. Further we discuss the development and the progress in creating light-induced gratings for neutron diffraction, culminating in the setup of an interferometer for cold neutrons. Experiments performed on the photo-neutronrefractive materials are reviewed and the variety of corresponding results obtained is presented including a discussion of their impact on material science, neutron optics, and the foundations of physics.