A non-symmetrical diarylethene with imidazo [1, 2-a] pyridine ring on one end and thiophene ring on the other end, 1, 2-dicyano-1-(2-methylimidazo [1, 2-a] pyridin-3-y1)-2-(2, 4, 5-trimetyl-3-thieny1) ethene 2Z underwent a hexatriene-cyclohexadiene type reversible ring-closure reaction by photoirradiation, while an only Z–E isomerization was observed for a symmetrical diarylenthene with two imidazo [1, 2-a] pyridine rings, 1, 2-dicyano-1, 2-bis ( ...