Rotationally resolved resonant two-photon ionization (R2PI) spectra of ScCo and YCo are reported. The measured spectra reveal that these molecules possess ground electronic states of 1Σ+ symmetry, as previously found in the isoelectronic Cr2 and CrMo molecules. The ground state rotational constants for ScCo and YCo are B0″=0.201 31(22) cm-1 and B0″=0.120 96(10) cm-1, corresponding to ground state bond lengths of r0″=1.812 1(10) Å and r0″=1.983 0(8) Å, respectively. A single electronic band system, assigned as a 1Π←X 1Σ+ transition, has been identified in both molecules. In ScCo, the 1Π state is characterized by T0=15 428.8, ωe′=246.7, and ωe′xe′=0.73 cm-1. In YCo, the 1Π state has T0=13 951.3, ωe′=231.3, and ωe′xe′=2.27 cm-1. For YCo, hot bands originating from levels up to v″=3 are observed, allowing the ground state vibrational constants ωe″=369.8, ωe″xe″=1.47, and ΔG1/2″=365.7 cm-1 to be deduced. The bond energy of ScCo has been measured as 2.45 eV from the onset of predissociation in a congested vibronic spectrum. A comparison of the chemical bonding in these molecules to related molecules is presented. [ABSTRACT FROM AUTHOR]