As one of the most abundant molecules in the universe, the long history of spectroscopic studies of the dicarbon molecule, C 2 , reaches back two centuries. While many electronic band systems with upper states below the lowest dissociation threshold have been well characterized, much less is known about transitions to higher-lying states. Here, we report the observation of a new band system of C 2 from the lowest triplet state a 3 Π u through a resonance-enhanced multiphoton ionization scheme. The upper state is identified as 1 3 Σ g + , which is determined to be 61539.0 cm -1 (7.630 eV) above ground state X 1 Σ g + . The spectroscopic parameters determined for the 1 3 Σ g + state are in excellent agreement with those predicted by the high-level ab initio calculations. This study paves the way for systematic investigations of the photoabsorption and photodissociation of C 2 in the vacuum ultraviolet region, which has important applications in the field of astrochemistry.