Nanocube CuInSe₂ (CIS) thin films have garnered significant interest due to their prospective applications in photovoltaic devices, thermoelectric systems, and optoelectronic devices. This study examines the photoluminescence (PL) characteristics, microstructure, and electrical properties of CIS thin films, which are crucial for understanding their performance in these applications. Copper chloride (CuCl₂) and indium chloride (InCl₃) were used to make Cu and In. Sodium seleno sulphate (Na₂SeSO₃) was used to make Se. Triethanolamine (C₆H₁₅NO₃), a complexing agent, and hydrochloric acid (HCl) were used to change the pH of the deposition solution. This work structure provides a thorough analysis of the topic, merging theoretical frameworks with practical applications and encouraging further investigation into enhancing the properties of CuInSe₂ thin films for solar energy applications. CuInSe₂ thin films show interesting photoluminescence properties that are closely related to their microstructure and electrical properties. The analysis of these films as semiconductors yields significant insights into their performance and prospective applications. The XRD pattern shows presence of the Nano crystalline thin film. The lattice parameters a and c derived from the XRD patterns of the CBD as deposited CuInSe₂ thin film were determined to be 5.782 Å and 11.621 Å, respectively. The peaks are matches with JCPDS Card Number: 40-1487. The analysis of all TEM images revealed a uniform cubic nanostructure with an average particle size of approximately 129 nm. The band gap energies derived from the absorbance spectra are 1.72, 1.91, 2.43, and 2.55 eV for samples D1, D2, D3, and D4, respectively. The photoluminescence spectra of CuInSe2 thin films generally display a distinct emission peak, linked to the band-to band transition. The electrical conductivity of the nanocrystalline CuInSe2 thin films increased as the temperature rose. TEP measurements show that the CuInSe₂ thin films made were n-type.