The Pauli equation can be derived from a special case of the equation.
It predicts the existence of antimatter particles, with the same mass and spin, but with the opposite charge. In 1931, Dirac predicted the existence of positrons, one year before the particles were found in an experiment.
It explains why the spin of the electrons in the Stern–Gerlach experiment acts like a magnet, which splits the silver atoms according to their spin.
Dirac Equation also explains the behaviour of electron in two-dimensional Graphene sheet where the electron is set free due to the lack of interaction between elections thus making the electron behave massless.