The study of the electrostatic potential (ESP) provides a perceptive understanding of the distribution of charges within the molecule (see Figure ). The ESP of aza-BODIPY molecules containing DPA and TPA groups exhibit significant differences. The region with a more negative potential, is denoted by red regions, is predominantly situated on the F atoms of the aza-BODIPY group. However, the DPA and TPA group exhibits a net positive potential, indicated by blue regions. This observation suggests that the aza-BODIPY group acts as the electron-acceptor group, while the DPA and TPA group serves as the electrondonor group which results in ICT which play a major role in NLO properties of the molecule. A model molecule that has gained a lot of attention from both experimentalists and theorists. The NLO properties of p-nitroaniline is also calculated using ω*B97XD/6-31G* functional and basis set to compare its results with PPAB-D-π-A structures (see Table ).