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Manipulation of periodic micro/nanostructures in polymer film is of great importance for academics and industrial applications in anticounterfeiting. However, with the increasing demand on information security, materials with time‐dependent features are urgently required, especially the material where the same information can appear more than once on the time scale. Here, one concise strategy to realize time‐dependent anticounterfeiting and "double‐lock" information encryption based on a host‐guest system is proposed, with one photoresponsive azopolymer as the host and one liquid‐crystalline molecule as the guest. The system exhibits a tunable mass transport in pre‐designed periodic micro/nanostructures by tailoring the process of cis‐to‐trans recovery of azo groups and assembly of mesogenic trans‐isomers, resulting in a dynamic structural color in film. Taking advantage of this extraordinary feature, time‐dependent dynamic anticounterfeiting has been achieved. More importantly, the time of each state's appearance in the whole process can be modulated by changing the host‐guest ratio. Combining the manipulatable process of mass transport with the unique decoding method, the stored information in film can be decrypted correctly. This work provides an unprecedented dynamic approach for advanced anticounterfeiting technology with a higher level of security and high‐end applications in information encryption. [ABSTRACT FROM AUTHOR]

Photoluminescence is one of the most meticulous ways to manipulate light energy. Typical photoluminescent emitters are mostly stable substances with a pure photophysical process of spontaneous photon‐emission from their excited states. Intermediate emitters are elusive attributing to their synchronous energy transfer process including photophysical and incomplete photochemical pathways. An intermediate emitter containing radicals is more difficult to be observed due to its inherent chemical reactivity. Here, these challenges are overcome by spontaneously formed space limitations in polymer crosslinking networks meanwhile chemically active intermediates are captured. These doublet intermediates exhibit unique long‐wavelength emissions under chemically crosslinking confinement conditions, and their luminous mechanism provides a novel perspective for designing intermediate emitters with liquid‐crystal character and photoresponsive features towards spatiotemporal encryption, promising for the detection of photochemical reactions and the development of fascinating luminescent systems. [ABSTRACT FROM AUTHOR]