**Abstract**

2D perovskite nanoparticles have a great potential for using in optoelectronic devices such as Solar Cells and Light Emitting Diodes within their tuneable optic and structural properties. In this chapter, it is aimed to express "relation between chemical structures and photo-physical behaviours of perovskite nanoparticles and milestones for their electronic applications". Initially, general synthesis methods of perovskite nanoparticles have been explained. Furthermore, advantages and disadvantages of the methods have been discussed. After the synthesis, formation of 2D perovskite crystal and effects on shape factor, particle size and uniformity of perovskite have been explained in detail. Beside these, optic properties of luminescent perovskite nanoparticles have been summarized a long with spectral band tuning via size and composition changes. In addition, since their different optical properties and relatively more stable chemical structure under ambient conditions, a comprehensive compilation of opto-electronic applications of 2D perovskite nanoparticles have been prepared.

**Keywords:** perovskite, nanoparticle, nanocrystal, opto-electronics, solar cells, OLEDs, fluorescence
