To realize light-responsive phase chirality from an achiral macrogelator in the solid state, a disc-shaped achiral macrogelator (B1AZ) was newly synthesized. B1AZ was self-assembled into a lamello-columnar structure in the bulk state, while single-handed helical fibrils (HF) with 400 nm of helical pitch were constructed by side-by-side lateral association of achiral B1AZ molecules in carvone chiral solvents. Even after the elimination of chiral solvents, the helical morphology and its chiroptical properties were precisely preserved. However, HF was not sensitive to UV light due to intense lateral packing. For remote-controlling the helical morphology, a single-helix (HS) with an 18 nm helical pitch was formed by utilizing cis-B1AZ sol. Upon irradiation with UV light, HS was transformed into spheroids (S) because of the trans-to-cis photo-isomerization of the azobenzene (AZ) of B1AZ. The photo-switchable phase chirality can be applied in light-responsive smart materials.
