In　this　article,　the　photophysical　properties　of　DHPs,　including　1,2-DHPs　and　1,4-DHPs,　were　studied　experimentally　and　theoretically.　Their　structural　differences　bring　about　different　photophysical　properties,　and　also　lead　to　different　photochemical　properties.　Specifically,　a　series　of　different　substituted　1,2-DHPs　and　1,4-DHPs　were　synthesized　to　measure　their　UV–Vis　absorption　and　fluorescence　emission　spectra　in　diluted　solutions　and　theoretical　calculations　were　performed　at　the　density　functional　theory　(DFT)　level.　To　describe　the　reactivities　of　the　DHPs,　time-dependent　density　functional　theory　(TDDFT)　was　used　to　optimize　their　ground-　and　excited-state　structures,　and　their　electronic　excitation　energies　were　calculated　at　the　B3LYP-D3/def2-TZVP　level.　Frontier　molecular　orbitals　and　electron-hole　distribution　analyses　were　used　to　illustrate　the　electron　transition　types.　The　differences　between　the　ground-　and　excited-state　structures　of　the　different　DHPs　were　characterized　by　carrying　out　a　root-mean-square-deviation　(RMSD)　analysis.　©　2023　Elsevier　B.V.