Two-dimensional (2D) coplanar heterostructure enables high-performance optoelectronic devices, such as p-n heterojunctions. However, realizing site-controllable and shape-specific 2D coplanar heterojunctions composed of two semiconductors with the same crystal orientation still requires the development of new growth methods. Here, a route to fabricate MoS 2 -MoTe 2 coplanar heterojunctions with the same crystal orientation is reported by exploiting the properties of phase transition and atomic rearrangement during the growth of 2H-MoTe 2 . Raman spectroscopy and electron microscopy techniques reveal the chemical composition and lattice structure of the heterostructure. Both MoS 2 and MoTe 2 in the heterojunction are single crystals and have the same lattice orientation, and their shapes can be arbitrarily defined by electron beam lithography. Electrical measurements show that the MoS 2 and MoTe 2 channels exhibit n-type and p-type transfer characteristics, respectively. The coplanar epitaxy technology can be used to prepare more coplanar heterostructures with novel device functions.