Elastomeric Intrinsic Optical Anti‐Counterfeiting with Dual‐Color RTP from Dual n→π* Transition and Enhanced Intersystem Crossing

Abstract Introducing N→B coordination on benzeneborate theoretically generates new n→π* transition and further usage as polymeric molecular extenders bring elastomeric intrinsic room‐temperature phosphorescence (RTP). However, low probability of phosphorescence arises from the narrow energy gap between the n→π* transition, whose related RTP probably lacks effective intersystem crossing (ISC), and the π→π*‐transition‐based fluorescence of benzeneborate. This work designs a para ‐phenyleneborate esterified by two N→B‐coordination‐based twist‐boat–boat (TBB) rings, activating a new n→π* transition of “N,N to para ‐phenyleneborate,” with much lower transition energy than the traditional n→π* transition of “N to phenylborate,” generating first‐reported dual‐color RTP. The conformation‐fixed dual TBB ring further reduces nonradial transition and enhances ISC, thus bringing RTP‐companying triple dependency on excitation, temperature, and delay time, and then achieving 12‐level optical encryption. Using this intrinsic RTP block as elastomeric molecular extender also integrates the self‐healing properties of dynamic borate ester bonds and acid/base/waterproof from TBB‐fixing N→B precoordination, enhancing adaptability in application scenarios.