In order to enrich the variety of copper sulfide and enhance its currently existing applications, CuS nestlike hollow spheres assembled by microflakes were successfully synthesized through an oil−water interface route employing copper chloride, carbon disulfide, and sulfur as the starting materials in the presence of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. The composition, morphology, and structure of the product were characterized by X-ray powder diffraction, energy dispersive spectrometer, scanning electron microscopy, and transmission electron microscopy. The optical properties of the copper sulfide microstructures were investigated by UV−visible absorption spectra. Nestlike CuS microstructures were also explored as an additive to promote the thermal decomposition of ammonium perchlorate, and a thermogravimetric analysis technique was applied to investigate its catalytic performance. The results demonstrate that the product possesses good optical quality and catalytic performanc...