Advanced hybrid fibrous materials based on polyacrylonitrile (PAN) and CuS/ZnS core/shell nanocrystals (NCs) were successfully prepared as efficient visible-light photocatalysts. The first step in the development of these novel hybrids was the synthesis of CuS/ZnS core/shell NCs with high photocatalytic activity under visible light irradiation. Further, CuS/ZnS-in-PAN hybrids were fabricated by electrospinning of PAN and CuS/ZnS NCs mixture, resulted in the distribution of NCs mainly into the PAN fibers. Purposefully, by simultaneous electrospinning of PAN solution and electrospraying of CuS/ZnS NCs dispersion, CuS/ZnS-on-PAN hybrids were obtained, as well. Thus, in one-step, NCs were selectively deposited "in" the PAN fibers or "on" the surface along the length of PAN fibers. The morphology of the hybrid materials was observed by scanning electron microscopy, while the distribution and crystallinity of the CuS/ZnS NCs were determined by high-resolution transmission electron microscope equipped with the selected area electron diffraction. The prepared CuS/ZnS-in-PAN and CuS/ZnS-on-PAN hybrids exhibit excellent photocatalytic activity even after threefold use in degradation of Rhodamine B under visible-light irradiation. Thus, the electrospun fibrous hybrids are very promising for design of a visible-light photoreactors for waste water treatment. [GRAPHICS] .