Ferromagnetic Interactionswithin a Dimer of a π‑Extended1,2,4-Benzotriazin-4-yl

1,3,7-Triphenyl-4,8-dihydro-1<i>H</i>-imidazo[4,5-<i>g</i>][1,2,4]benzo­triazin-4-yl, a stable radical, forms 1 D π stacks. These stacks consist of dimers with alternating interplanar distances measuring 3.443 Å (short) and 4.169 Å (long). Magnetic susceptibility (χ<i>T</i>) reaches its peak at 18 ± 4 K, signifying the presence of a dimer with ferromagnetic interactions, quantified by 2<i>J</i> = 18.1 cm^–1. The magneto-structural relationship is corroborated by DFT calculations.