In liquid-crystal colloids where colloidal spheres are dispersed in liquid crystals, we investigated photochemical manipulation of colloidal structures and optical properties. By modulating surface properties of colloidal spheres on the basis of photoisomerization of photochromic compounds, we achieved a control of aggregation and dispersion of the spheres. A variety of colloidal superstructures could be fabricated by illumination of appropriate patterned light onto the liquid-crystal colloids. In addition, we could manipulate light-scattering properties of the liquid-crystal colloids by photochemical modulation of phase structures of liquid crystals. It is strongly expected that the liquid-crystal colloids will be applied to practical devices in various industrial fields.