Flexible inorganic double helical semiconductors similar to DNA have fueled the demand for efficient materials with innovative structures and excellent properties. The recent discovery of tin phosphide iodide (SnIP), the first carbon-free double helical semiconductor at an atomic level, has opened new avenues of research for semiconducting devices such as thermoelectric and sensor devices, solar cells, and photocatalysis. It has drawn significant academic attention due to its high structural flexibility, band gap in the visible spectrum range, and non-toxic elements. Herein, the recent progress in developing SnIP, including its prestigious structure, versatile and intriguing properties, and synthesis, is summarized. Other analogues of SnIP and SnIP-based hybrid materials and their applications in photocatalysis are also discussed. Finally, the review concludes with a critical summary and future aspects of this new inorganic semiconductor.