Methylammonium lead halide (MAPbX3) perov- skites exhibit exceptional carrier transport properties. But their commercial deployment as solar absorbers is currently limited by their intrinsic instability in the presence of humidity and their lead content. Guided by our theoretical predictions, we explored the potential of methylammoni- um bismuth iodide (MBI) as a solar absorber through de- tailed materials characterization. We synthesized phase- pure MBI by solution and vapor processing. In contrast to MAPbX3, MBI is air stable, forming a surface layer that does not increase the recombination rate. We found that MBI luminesces at room temperature, with the vapor-pro- cessed films exhibiting superior photoluminescence (PL) decay times that are promising for photovoltaic applica- tions. The thermodynamic, electronic, and structural fea- tures of MBI that are amenable to these properties are also present in other hybrid ternary bismuth halide com- pounds. Through MBI, we demonstrate a lead-free and stable alternative to MAPbX3 that has a similar electronic structure and nanosecond lifetimes.