Resonant two photon ionization (R2PI) spectroscopy was used to obtain detailed spectroscopic information on the neutral and cation ground states of the jet-cooled molecules V-2, VNb, and Nb-2. By recording photoionization efficiency (PIE) spectra, their adiabatic ionization potentials were determined to be 51 269(5) cm(-1) (V-2), 51 554(10) cm(-1) (VNb), and 51 359(10) cm(-1) (Nb-2). In VNb, we used different ionization routes to determine that the splitting between the Omega=0 and Omega=1 spin-orbit components of the X (3) Sigma(-) ground state was 230(3) cm(-1). In the case of V-2 and VNb, two thresholds were observed in the PIE spectra recorded via Omega=1 intermediate states. We were thus able to assign the ground states of V-2(+) and VNb+ as having (4) Sigma(-) symmetry, with second-order spin-orbit splittings of 20(3) and 82(3) cm(-1), respectively. A simple model was applied to calculate the locations of the (1) Sigma(+) and (2) Sigma(+) states which are responsible for the second-order spin-orbit splitting of the neutral and cation ground states, respectively. One-color R2PI spectroscopy was employed to determine the bond dissociation energy of VNb, the result D-0(0)=30 562(10) cm(-1) being obtained. The implications of our measurements regarding the relative bond strengths of the neutral and cationic dimers are discussed.