Fig. 2. Top to bottom: EPR spectra of 2-methyl-1,3-bis(biphenylylene)propenyl radical (toluene, 296 K), Coppinger's radical (toluene, 190 K) and zinc 5-cyclohexyl-10,15,20-triphenylporphyrin cation radical (CH_2Cl_2, 296 K).