2D black phosphorus (BP) and rhenium dichalcogenides (ReX , X = S, Se) possess intrinsic in-plane anisotropic physical properties arising from their low crystal lattice symmetry, which has inspired their novel applications in electronics, photonics, and optoelectronics. Different from BP with poor environmental stability, ReX has low-symmetry distorted 1T structures with excellent stability. In ReX , the electronic structure is weakly dependent on layer numbers, which restricts their property tunability and device applications. Here, the properties are tuned, such as optical bandgap, Raman anisotropy, and electrical transport, by alloying 2D ReS and ReSe . Photoluminescence emission energy of ReS Se monolayers (x from 0 to 1 with a step of 0.1) can be continuously tuned ranging from 1.62 to 1.31 eV. Polarization behavior of Raman modes, such as ReS -like peak at 212 cm , shifts as the composition changes. Anisotropic electrical property is maintained in ReS Se with high electron mobility along b-axis for all compositions of ReS Se .