Open-shell organic radicals exhibit exceptional photophysical properties due to their unique electronic structures. Herein, we report the 2,5,8-tribromophenalenyl radical (Br-PLY) as a stable, emissive phenalenyl derivative. Br-PLY shows a monomer−π-dimer equilibrium in solution and emits light from its monomeric radical state. Its high air stability (t1/2 ≈ 40 h) and long-lived emission (τ = 252 ns) demonstrate the potential of phenalenyl radicals as promising luminescent materials beyond trityl-based systems.