Titanium dioxide Inverse opals were prepared by the typical method of infiltration with a liquid precursor (LP-IOs) and by an improved method in which the infiltration step is done with a suspension of TiO2 nanoparticles (NP-IOs). A thorough characterization study was performed on both types of preparations in order to highlight the differences between the resulting inverse opal samples. The formation of a compact overlayer in LP-IO samples inherent to the use of a liquid precursor proved to be detrimental for the optical and photonic properties of the inverse opals. NP-IO samples, on the other hand, showed improved optical, photonic, and mechanical properties. The photocatalytic degradation of a model compound (a well-known dye, methylene blue) revealed that NP-IO samples are able to degrade the model compound at a higher rate due to the absence of the compact overlayer which acts as a mass and light blocking barrier.