<p>Perovskite-structured semiconductors have attracted significant attention due to their low-cost material constituents and simple solution-fabrication processes. This study addresses two major issues hindering the commercial implementation of Pb-based hybrid inorganic halide perovskites: instability and lead toxicity. To reduce toxicity, lead was replaced with bismuth, rubidium, cesium, and holmium were used instead of organic cations to enhance material stability. Cesium-bismuth-iodide (Cs₃Bi₂I₉), rubidium-bismuth-iodide (Rb₃Bi₂I₉), and holmium-bismuth-iodide (Ho₃Bi₂I₉) powders were synthesized using a chemical precipitation method. The structural properties were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet–visible spectroscopy (UV–Vis) were employed to identify functional groups and optical characterization. From the structural analysis, parameters such as crystallite phases, crystallite size, strain, microstrain, dislocation density, and crystallinity were calculated using the XRD pattern. Additionally, the crystallite size was calculated using Williamson-Hall analysis and Scherrer's formula. SEM studies demonstrated the formation of aggregate crystals of various sizes. The optical absorption and bandgap were determined using Tauc plots from the UV–Vis spectra. The calculated bandgaps were 2.75, 2.63, and 2.96&#xa0;eV for Cs₃Bi₂I₉, Rb₃Bi₂I₉ and Ho₃Bi₂I₉ perovskites, respectively. As no previous reports on Ho₃Bi₂I₉ perovskite exist, this study marks the first exploration of the synthesis and analysis of Ho₃Bi₂I₉ perovskite. Our results indicated that the prepared perovskite-structured semiconductors are suitable for optoelectronic device applications.</p>