In conclusion, we synthesized and characterized Ag 3 Au(Se,Te) 2 solid solutions for the first time. The lattice constants increased linearly with Te incorporation, by 4% at x = 1. We observed the optical band gaps from Ag 3 AuSe 2 to Ag 3 AuTe 2 vary smoothly from 0.9 eV to 0.6 eV, with a slight upward bowing for intermediate compositions. The minimal band gap achieved in the Tealloyed Ag 3 AuSe 2 was 0.6 eV for x = 0.9. Our DFT-mBJ band structure calculations yielded qualitatively similar features and larger band gaps compared to the previous PBE-based simulations. The mBJ gaps were in excellent agreement with our experimental optical band gaps for both selenide and telluride, as expected, since mBJ is a hybrid functional. Based on these results, external pressure on the telluride would be the most viable route if the goal is to access a narrower band gap.