A light-conducting component, in particular finished concrete part in the form of a masonry brick, for constructions and buildings. The component is produced in a casting mold by casting into at least one casting building material and the optical waveguide is made of a light-conducting building material, e.g. PMMA polymer or glass, which is accessible at at least two positions on the outer surface of the light-conducting component for the input of light and output of light. The optical waveguide is configured as a self-supporting 2D or 3D lattice body composed of rods having a thickness/diameter of greater than 1 mm. The self-supporting 2D or 3D lattice body has approximately the same or an only slightly smaller width (W), or length (L), or base dimensions (W, L), or total external dimensions (W, L, H) than the casting mold itself.