Triphenylmethyl (trityl) radicals have shown potential for use in organic optoelectronic applications, but design of practical trityl structures has been limited to donor/radical charge-transfer systems due to the poor luminescence of alternant symmetry hydrocarbons. Here, we circumvent the symmetry forbidden transition of alternant hydrocarbons via excited state symmetry breaking in a series of phenyl substituted tris(2,4,6-trichlorophenyl)methyl (TTM) radicals. We show that threefold phenyl substitution enhances the emission of TTM radical, and that steric control modulates the optical properties in these systems. Simple ortho-methylphenyl substitution boosts the photoluminescence quantum efficiency from 1% (for TTM) to 65% at a peak wavelength of 612 nm (for 2-T3TTM) in solution. In the crystalline solid state, neat 2-T3TTM radical shows a remarkably high photoluminescence quantum efficiency of 25% for emission peaking at 706 nm. This has implications in the design of aryl substituted radical structures where electronic coupling of the substituents influences variables such as emission, charge transfer and spin interaction.