Resonant two-color two-photon ionization spectra of C 9 H 3 , C 1 1 H 3 , and C 1 3 H 3 have been observed in the gas phase and are found to exhibit remarkably similar vibrational structure. All have origins in the 18,800-19,300cm - 1 region and a characteristic ~40cm - 1 progression. Several pieces of spectroscopic information suggest a common moiety incorporating a strong, localized electronic transition, consistent with a low ionization potential as compared to other hydrocarbon radicals. Several possible structural motifs are discussed in relation to plasma, combustion and interstellar chemistry.