Two polytriphenylamines (PTPAs) (P1 and P2) with aggregation induced emission (AIE)-active tetraphenylethylene side groups have been designed and successfully synthesized. Both polymers only faintly emit in dilute solution but show strong emission in aggregated state, meaning that they are AIE-active. The detection of 1,3,5-trinitrobenzene (TNB) vapors has been investigated by photoluminescence (PL) quenching in polymer films. High solid state quantum yields and donor-acceptor interactions of the electron-rich PTPA chains with the TNB analyte, hereby, induce a high sensing sensitivity, both for P1 and P2 films towards TNB vapor. Contacting thin P1 and P2 films with saturated TNB vapor, the PL intensity was quenched by 85% for P1 and 89% for P2 within 600 s, respectively. The sensing process is reversible, >90% of the PL is recovered, also after repeated cycling. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 53, 1753-1761