Abstract
The title compounds containing diamagnetic Ga are superconductors. The nitrobenzene salt shows a broad metal-semiconductor transition at 160 K but becomes superconductor below 7.5 K. The Meissner volume of a powder sample at 1.8 K is estimated at 31%. The pyridine salt also has a broad upturn in resistance at 130 K, a re-entrant metallic phase below 60 K, and a resistance loss below 1.5 K. The loss vanishes with applying magnetic field, suggesting that it is also superconductor.