Electronic transitions of cobalt monochloride and cobalt monoiodide have been studied using laser vaporization-reaction free jet expansion and laser induced fluorescence spectroscopy in the near infrared region. The observed transitions have been identified as the [10.3] (3)Phi(4)-X (3)Phi(4) transition of CoCl and [11.0] (3)Phi(4)-X (3)Phi(4) transition of CoI. The magnetic hyperfine structure arising from the cobalt nucleus with I=7/2 was resolved and analyzed. Accurate rotational and hyperfine parameters for the [10.3] (3)Phi(4) and X (3)Phi(4) states of CoCl and [11.0] (3)Phi(4) and X (3)Phi(4) states of CoI have been obtained. Comparison of Fermi contact parameters, b(F), for the upper states indicated that the observed [10.3] (3)Phi(4)-X (3)Phi(4) transition of CoCl and [11.0] (3)Phi(4)-X (3)Phi(4) transition of CoI have arisen from the promotion of an electron from the bonding sigma orbital to a slightly antibonding sigma orbital. Observed low-lying (3)Phi states of the cobalt monohalides and hydride are also compared and discussed. (C) 2003 American Institute of Physics.