Two halogenated chalcones B3B2SC and C3B2SC were synthesized for NLO applications. Single-crystal X-ray diffraction, spectroscopic (NMR and FT-IR), thermal and DFT studies were performed. Both the crystals are crystallized in the monoclinic non-centrosymmetric Pn space group. The SHG efficiency of both the chalcones is higher than urea. The third-order NLO parameters, optical limiting and optical switching properties of the chalcones were investigated by Z-scan method using a CW laser at 532 nm. The experimental and computational linear and nonlinear optical studies revealed that both the chalcone are promising materials for NLO applications.