This project explores the fabrication of three-dimensional photonic crystals via a bottom-up self-assembly approach. Starting from polymeric tetrahedral building blocks, colloidal crystals are formed and subsequently infiltrated with high-refractive-index materials such as titania or silicon. Removal of the original template yields an inverted photonic crystal structure with precise periodicity and strong dielectric contrast. By tuning lattice constants and introducing controlled disorder, these materials offer a powerful platform for studying light localization and engineering next-generation photonic components. The process combines scalability with fine structural control, bridging fundamental research and advanced optical technologies.