We present an overview of recent investigations of photopolymerizable nanocomposite photonic materials in which, thanks to their high degree of material selectivity, recorded volume gratings possess high re- fractive index modulation amplitude and high mechanical/thermal stability at the same time, providing versatile applications in light and neutron optics. We discuss the mechanism of grating formation in holographically exposed nanocomposite materials, based on a model of the photopolymerization-driven mutual diffusion of monomer and nanoparticles. Experimental inspection of the recorded grating̊qs morphology by various physico-chemical and optical methods is described. We then outline the holographic recording properties of volume gratings recorded in photopolymerizable nanocomposite materials consist- ing of inorganic/organic nanoparticles and monomers having various photopolymerization mechanisms. Finally, we show two examples of our holographic applications, holographic digital data storage and slow-neutron beam control. Such demonstration with high performance clearly shows the usefullness of photopolymerizable nanocomposite photonic materials.