Theoretical studies on the electronic and thermodynamic properties of several electronic states are presented for the ScC3 molecule and the ScC3- anion employing state-of-the-art techniques that included up to 13 million configurations. The ground and the low-lying electronic states of these two species have been predicted to have C-2v ring structures. On the basis of our computed results on the low-lying excited electronic states, we have suggested assignment of the observed anion photodetachment spectra of ScC3-. Thermodynamic properties of reactions involving ScC3 are corrected using the computed gas-phase properties of the molecule and the partition functions. Thermodynamic functions of ScC3- are also determined by fitting the available experimental data with thermodynamic energy cycles. The nature of bonding in the neutral and the anionic carbides has been considered.