Photocyclization of 8-aryloxy-3-phenylbenzo[e][1,2,4]triazines leads to -delocalized helicene radicals 1[n] (n = 5, 6, 7) containing the ring-fused 1,4-dihydro[1,2,4]triazin-4-yl as a spin source. Single crystal XRD revealed that the photocyclization to...