Diffraction methods using neutrons and/or high-energy X-rays offer unique opportunities for investigating various aspects of importance for the development of intermetallic titanium aluminides (TiAl) alloys. Despite their different nature, high-energy X-rays and neutrons are both suited for performing diffraction as well as scattering experiments in materials science. A common feature of structural materials, including TiAl alloys, is the dependency of their properties on phase composition and the arrangement of the constituting phases. Employing high-energy X-ray diffraction (HEXRD) allowed for in situ monitoring of the phases evolution. Transmission electron microscopy (TEM) is a method that would allow determining phase fractions in lamellar grains, although at the expense of time-consuming sample preparation and the restriction to small sample volumes. By diffraction methods, the phase fractions can be determined with high accuracy even in the instance that lamellar colonies are present in the material.