Lead halide perovskites are widely recognized for their exceptional defect tolerance, setting the benchmark for high-performance optoelectronic applications. Conversely, low-toxicity perovskite-inspired materials (PIMs) typically exhibit suboptimal optoelectronic performance, primarily due to their intrinsic susceptibility to defects. In this study, we address this limitation by exploring the effects of halide vacancies in PIMs through the synthesis of non-stoichiometric Cs