HgCdTe remains to be the most important material for infrared photodetectors despite numerous attempts to replace it with alternative materials. It is interesting, however, that none of these competitors can compete in terms of fundamental properties. In addition, HgCdTe exhibits nearly constant lattice parameter that is of extreme importance for new devices based on complex heterostructures. The development of sophisticated controllable vapor phase epitaxial growth methods, such as MBE and MOCVD, has allowed fabrication almost ideally designed heterojunction photodiodes. In the paper examples of novel devices based on heterostructures operating in long wavelength, middle wavelength and short wavelength spectral ranges are presented. Recently, more interest has been focused on p-on-n junctions heterostructures. As the infrared technology continues to advance, there is a growing demand for multispectral detectors for advanced IR systems with better target discrimination and identification. HgCdTe heterojunction detectors offer wavelength flexibility from medium wavelength to very long wavelength and multicolor capability in these regions. The main challenges facing all multicolor devices are more complicated device structures, thicker and multilayer material growth, and more difficult device fabrication, especially when the array size gets larger and pixel size gets smaller.