Recent years have witnessed a paradigm shift with the advent of perovskites, a class of materials with a distinct CaTiO₃-type crystalline structure that show remarkable promise across a wide array of applications, including photovoltaics, photodetectors, lighting, lasers, and so forth. Among them, the development of two-dimensional (2D) perovskites has garnered significant attention due to their tunable structures (mainly DJ and RP structures) and enhanced stability in comparison to their three-dimensional (3D) counterparts.

Amidst the burgeoning research on perovskites, on the other side, all-organic perovskites stand out as a particularly intriguing subset [2]. Unlike traditional perovskites that typically comprise all-inorganic (e.g., CsPbBr₃) or organic-inorganic hybrid components (e.g., (PEA)₂PbI₄), all-organic perovskites are composed entirely of carbon- or nitrogen-based molecules. Importantly, the absence of heavy metals in their structures addresses one of the primary concerns associated with conventional perovskites—environmental toxicity. Therefore, 2D all-organic perovskites offer a compelling avenue for sustainable material development, leveraging the versatility and abundance of organic chemistry to create environmentally benign and highly customizable functional materials. What’s more, this distinction is not merely compositional but extends to their properties and potential applications. According to the structure-function relationship, the ability to fine-tune the electronic and optical properties of the 2D all-organic perovskites through molecular engineering opens up new possibilities for their application in optoelectronics and beyond. Nevertheless, the journey towards viable 2D all-organic perovskites is fraught with challenges, notably the difficulty in achieving the desired accessibility and performance characteristics that metal-containing perovskites are known for. The key significant hurdles are the steric hindrance posed by larger organic molecules and the weaker interactions between organic layers compared to their inorganic counterparts.