Systems constructed by periodic patterns of materials with different dielectric constants are regarded as photonic crystals, capable of controlling and manipulating light flow in a certain frequency range, commensurate with the length scale of the crystal. The holy grail in photonic materials, diamond, still remains a challenge to synthesize at the colloidal length scale. Anisotropic nanoparticles prove a promising route for colloidal diamond, with entropy motivating face-to-face alignment, leading to self-assembly of complex crystals. These principles led to the discovery that truncated tetrahedral nanoparticles would self-assemble diamond, although this route can lead to crystalline disorder, which will reduce or extinguish the photonic band gap. Here we explore new ways to assemble diamond, self-assembly with modified gyrobifastigial (mGBF) nanoparticles, whose shape is constructed from two anti-aligned triangular prisms. We demonstrate the parameter space which leads to the self-assembly of diamond and summarize the benefits of diamond self-assembled via the mGBF to previous methods. We also introduce a potential route for creating mGBF particles through dimerization of triangular prisms using attractive patches and report the impact of this substructure on the photonic properties.