A triphenylamine derivative decorated with an azobenzene group (TDA) was synthesized via a SuFEx click reaction and its polymer, poly(triphenylamine) (PTDA), was polymerized through a redox polymerization. More interestingly, its polymeric metal complex, PTDA‐Fe, can be simply obtained via one‐pot reaction between TDA and FeCl3 owing to TDA showing a strong affinity to the FeIII ion. The sandwich memory device based on PTDA nanofilms as active layers exhibited a binary memory performance. However, the memory device based on its polymeric metal complex exhibited a unique ternary memory behavior. The different memory performances should come from the different conductive mechanism. The mechanism of such ternary memory devices is illustrated based on both the theoretical calculation and experiments. Our work provides new insights into the preparation of novel materials for multilevel memory devices.