The magnetic study of bis{(5,6-dihydro-6-methylphenanthridin-5-oxyl-6-yl)}methane revealed a practically diamagnetic character, though the crystal structure analysis indicates the presence of two nitroxide groups in a molecule. Two chromophores form a "pseudo-ipso" pancake-like dimer. DFT calculation study confirmed the notably strong intramolecular antiferromagnetic coupling.