Benzanthrone derivatives namely 3-(4-methylpiperazin-1-yl)-7H-benzo[de]anthracen-7-one [Me-PBA] and 3-(4-phenylpiperazin-1-yl)-7H-benzo[de]anthracen-7-one [Ph-PBA] were exploited for their potential NLOphoric properties. We have unrevealed the relation between the chemical substitution and the nonlinear optical properties of the molecules. The third order NLO parameters of both the molecules in solution (0.01 M) were investigated using a continuous wave DPSS laser (532 nm) by Z-scan technique. The nonlinear absorption (NLA) profile of both the compounds was found to follow the two-photon absorption (TPA) model. Nonlinear absorption coefficient (β), nonlinear refractive index (n₂) and second-order hyperpolarizability (γ) were found to be maximum for methyl substituted dye compared to phenyl substituted dye at 532 nm laser wavelength. The evaluated optical limiting values and figure of merit reveal that the samples are best suited for optical limiting and all-optical switching at 532 nm wavelength. In addition, we have carried out detailed theoretical studies and our calculations at the DFT level of theory are consistent with the experimental NLO results. Both the dyes exhibit a large Stokes shift of around ∼100 nm. And both of them exhibit a bathochromic shift of around ∼60 nm in polar solvents.