Copper (II) selenide is primarily used in the field of semiconductor technology due to its favorable electronic and optical properties. It serves as a key material in the production of solar cells, where it acts as a light-absorbing layer, helping convert sunlight into electricity efficiently. Its narrow bandgap makes it suitable for use in photovoltaic devices and infrared detectors.

The compound is also employed in thermoelectric devices, where it helps convert waste heat into usable electrical energy, offering potential in energy recovery systems. Thin films of copper (II) selenide are applied in optoelectronic components such as photodetectors and sensors because of their sensitivity to light and electrical conductivity changes under illumination.

Additionally, it is researched for use in nanotechnology, particularly in the development of nanoparticles for catalytic applications, biomedical imaging, targeted drug delivery, and as a precursor in synthesizing other copper selenide phases with tailored properties. Its role in electrochemical applications, including lithium-ion, sodium-ion batteries, and supercapacitors, is also being explored due to its ability to participate in reversible redox reactions and improve capacity and lifespan.