The success of hybrid halide ABX3 perovskites semiconductors in the field of photovoltaics and optoelectronics in general has recently motivated the chemical synthesis and study of a plethora of related compounds, based on mixed metal-halide inorganic frame and an organic component [1,2]. Indeed, the relaxation of the size condition for the central A cation, to fit within the cavity between the BX3 octahedral and mathematically expressed by the Goldschmidt tolerance factor, opens the way for a huge library of novel compounds, as layered nanosheet-like 2D halide perovskites, 1D nanorod-like perovskite etc. [3] Here, we investigate the electronic properties of lead-deficient halide perovskites, a class of recently developed compounds including a fraction of large organic cations, which interrupts the 3D corner-shared connection of the BX3 octahedra and introduces ordered metal-halide vacancies in these materials [4,5,6]. We will discuss the effect of the progressive inclusion of lead-halide vacancies using DFT calculations (Figure 1) and group theory analysis. [1] D. Mitzi et al, Nature 369, 467-469 (1994) [2] C. Katan, N. Mercier, J. Even, Chem. Rev., 119, 3140-3192 (2019) [3] I. Garcia-Benito et al. Chem. Mater. 2018, 30, 22, 8211-8220 [4] Antonin Leblanc, et al. Angew Chem Int. Ed. 56, 16067 –16072 (2017) [5] A. Leblanc, et al. ACS Appl. Mater. Interf. 11, 20743-20751 (2019) [6] C. Zheng et al. J. Chem. Phys. 151, 234704 (2019)