Strategies　by　introducing　chiral　auxiliaries　into　the　photoreactive　substrate　1,4-dihydropyridines,　an　interesting　diastereoselectivity　of　2,3-dihydropyrroles　in　the　process　of　photochemical　ring　contraction　was　observed.　The　diastereoselectivity　of　(2R,3R)　and　(2S,3S)-2,3-dihydropyrroles　was　related　to　the　phenyl　group　and　the　chirality　of　C-4　in　1,4-dihydropyridines　and　similar　to　that　of　1,4-dihydropyridines.　The　yields　and　diastereomeric　excess　of　all　obtained　products　supporting　the　experimental　data　were　compared　and　discussed　in　theoretical　calculations.　A　concise　theoretical　study　was　used　to　explain　the　diastereoselectivity　observed　in　the　photochemical　ring　contraction　of　1,4-dihydropyridines　to　2,3-dihydropyrroles.　(C)　2021　Elsevier　Ltd.　All　rights　reserved.