Through NMF, we first examine the phase emergence behaviors in the BA-based quasi-2D HP system, having a short aliphatic chain and light molecular weight. At the top surface, it is found that low-n 2D HPs -particularly, n=1 -emerge across the whole compositional range (Component 2; Figure and Figure ). Additionally, a very weak PL peak centered at ~710 nm emerges-assigned to be α-CsPbI3 having a redshifted PL from the that of the 3D-like HPs, which quickly disappears within an hour (Figure ). This indicates that the α-CsPbI3 HP phase, with a cubic lattice structure, initially forms at the low annealing temperature, which is then quickly disintegrate or transform to other phases due to its intrinsic thermodynamic instability. Note that such a feature cannot be recognized by manual exploration of the PL spectra (Figure -S7), showing the effectiveness of NMF technique on studying such large datasets. Also, multiple low-n HPs (e.g., n=1-5) prominently emerge up to 30% of CsPbI3, which are then suppressed at the higher composition ratios (Component 3 in Figure )as seen in the corresponding PL spectra as a function of 3D ratios Figure . Meanwhile, the PL of the 3D-like phases -centered at ~700 nm -starts to emerge over 3D ratios over 40% (Figure ), suggesting that 3D-like phases start to develop. In contrast, for the case of BDA, with an additional ammonium head in the structure of the spacer molecule, multiple low-n HP phases (n=1-5), as well as the 3D-like phases emerge across the entire compositional range (Figure ,d and Figure ). It is found that the PL intensity of the latter phases gradually decreases over time, attributed to their poor stability. Note that the spectral signature of the emergence of α-CsPbI3 HP is not observed in this system, implying that BDA cannot manifest the construction of the cubic HP lattice. NMF-deconvolution reveals the similarity in global phase emergence behaviors between ThEA-and PEA-based quasi-2D HP systems (Figure and). Qualitatively, the deconvoluted PL features are also analogous to those in the BAbased system, rather than the BDA counterpart, indicating that the type of the spacer cations primarily determines the overall phase emergence behaviors. In both cases, at the top surface, n=1 and other low-n 2D HPs emerge at low-3D composition ratios, which are gradually suppressed up to the 3D ratio of 40% (Component 2 in Figure S10d, respectively). Above 40% and 60% for the ThEA-and PEA-based systems, respectively, these phases start to emerge again and then disappear over 90% 3D ratio. In both cases, NMF deconvolution captures the transient emergence of the α-CsPbI3 HP (Component 3), which survives longer times than that observed in the BA counterpart. This implies that the aromatic rings can provide better stability to the HP lattices.