In　this　article,　photophysical　characterizations　of　series　of　2,6-unsubstituented　1,4-dihydropyridines　(USDHPs)　were　described　by　UV-vis　absorption　and　fluorescence　emission　spectroscopies　in　diluted　solutions.　Their　maxima　show　an　intimate　relationship　with　the　substituent　position　on　the　DHP　ring　and　the　solvent　nature　had　an　influence　on　the　irradiative　lifetime　of　the　lowest　energy　transition.　In　order　to　get　insight　into　these　behaviours,　theoretical　calculations　were　performed　at　the　density　functional　theory　(DFT)　level.　The　geometrical　and　electronic　structural　variations　after　excitation　were　analyzed　and　the　natural　populatation　analysis　(NPA)　charge　distributions　in　the　excited　states　were　calculated　for　predicting　the　reactive　sites　of　US-DHPs,　which　is　meaningful　for　explaining　the　regioselectivity　of　their　photochemical　reactions.　(C)　2018　Elsevier　B.V.　All　rights　reserved.