<p>A nitro-substituted azo-chalcone chromophore was synthesized by a Mn-MOF-assisted microwave Claisen-Schmidt condensation and investigated using an integrated experimental and computational spectroscopic approach. ATR-FTIR, FT-Raman, ¹H/¹³C NMR, mass spectrometry, and DFT calculations confirmed the molecular structure and supported the main spectral assignments. UV–Vis spectra recorded in solvents of different polarity revealed a pronounced solvent-dependent modulation of the absorption bands, consistent with intramolecular charge-transfer (ICT) character. Acidic and basic media produced clear halochromic responses attributed to protonation/deprotonation equilibria and the consequent changes in conjugation and electronic distribution. TD-DFT/CPCM, frontier-orbital, and natural transition orbital analyses attributed these shifts to solvent-dependent excited-state stabilization and intramolecular charge transfer. Repeated acid–base switching showed reproducible absorbance changes over six cycles, supporting the reversible nature of the halochromic response. Overall, the results establish a structure–property relationship for the solvent- and pH-sensitive electronic response of azo-chalcone <b>5</b>.</p> Graphical abstract <p></p>