The optical characterization and optimization of nano- and two-dimensional (2D) materials are fundamental for advancing photonic devices and applications. This dissertation is divided into four different investigations on optics and presents an integrated approach combining experimental and computational methods to investigate and enhance the optical properties of these materials. First, light scattering phenomena was explored using random laser systems and numerical simulations to determine the scattering efficiency of different natural nanomaterials for various applications such as phototherapy devices. Second, hyper-Rayleigh scattering (HRS) technique was employed to characterize the second-harmonic generation, revealing nonlinear optical responses of nanocrystals. Additionally, the optical behavior of transition metal dichalcogenides (TMDs) under external excitations, such as varying electric fields, was systematically studied, providing a deeper understanding of their tunable properties and degradation mechanism. Finally, the optimization of nanomaterials was addressed through the application of a multi-objective genetic algorithm (MOGA), enabling the identification of geometrical configurations with enhanced optical properties for plasmonic applications.