The lack of firm data on many of the spectroscopic properties of CIO which have potential stratospheric diagnostic applications are emphasized. A characteristic vibration-rotation spectrum of C1O is described. Morse Franck-Condon factors and r-centroids are displayed for the A2II-X2II electronic band system. Quantitative estimates are made of absorption cross sections of certain bands, particularly for those of the v11=0 progression which lie beyond the ozone cutoof and thus are in principle observable from the ground and from space platforms.