Fig. 1. The formation and response of crystalline capsules of diarylethene 1. (a) Molecular structures of open-(1o) and closed-ring isomer (1c) and photo-release from a crystalline capsule. (b) A crystalline capsule of 1o including hexane solution of 1o. (c) After the capsule was broken with a needle, hexane solution leaked, and the intrusion of air bubbles into the capsule was observed (ESI Movie S1†). (d) Cross-section SEM image of a crystalline capsule shown in (c); hole size was ca. 30 × 70 μm. (e) Observation of the formation of crystalline capsule. A crystal was grown along with the formation of two capsule cavities (ESI Movie S2†). (f) A 1o crystal encapsulating BPEA in solution (left). Crystal irradiated with 450 nm light (centre). Crystal irradiated with 405 nm LED light, which released solution by a photosalient phenomenon (right). See also ESI Movie S3.† (g) A crystalline capsule of 1o encapsulating a BPEA crystal (left). Crystal irradiated with 405 nm light (centre). Continued irradiation with the 405 nm light, where the crystal released the contained crystal of BPEA by a photosalient phenomenon (right). See also ESI Movie S4.†.