The optical properties and bandgap energy of Cadmium Copper Sulfide (CdCuS) were investigated using the Successive Ionic Layer Adsorption Reaction (SILAR) method of thin film deposition. The experiment was conducted at a temperature 333k (60°C), and at three different cycles: 20, 30 and 40 respectively. UV-vis spectrophotometer was used in the characterization, and Origin Lab software was used in the computation and graph plotting. From the result obtained, the maximum transmittance and reflectance occur at the visible and infra-red regions in the electromagnetic spectrum. Also, the bandgap energy for 20, 30, and 40 cycles are approximately: 1.26eV, 1.38eV, and 1.57eV respectively. The analysis of the bandgap energy strongly suggests that increase in the bandgap value decreases the electrical conductivity, hence the substrate deposited at 40 cycles has the least electrical conductivity. Further analysis of the bandgap energy revealed that CdCuS deposited by SILAR method has prominent applications in optical devices and solar cells.