Fig. 4. Photoresponse of a crystalline capsule upon polarized light. (a) Relationship between long and short axes of the crystalline capsule and a- and b-axes of the crystal lattice. (b) Molecular packing of 1o in the crystal viewed from the (001) surface. (c) Schematic diagram of observed photosalient effect depending on polarization direction of UV light. Polarization direction is parallel to the white double arrow. (d) Polar plot of action spectrum of the crystal of 1o. The colouring of the crystal is dependent on the direction of polarized UV light. (e) Two crystalline capsules of 1o were placed orthogonally to each other on a slide glass. When 365 nm linearly polarized light was irradiated, the crystal which has its long axis perpendicular to the polarization direction showed colouration followed by jumping away (ESI Movie S9†). (f) Three crystalline capsules were placed together and oriented at angles 45° apart. The crystal whose long axis was perpendicular to the polarization direction jumped away at first, followed by the one rotated 45° from the polarization direction. The crystal whose long axis was parallel to the polarization direction remained largely unchanged (ESI Movie S10†).