The CaO-group attached to a molecular scaffold can function as an optical cycling center (OCC). Molecules functionalized with OCCs can be laser-cooled by scattering thousands of photons with a minimal loss of the population from the cycling pair of states (preferrably, the ground state and the lowest excited state). Laser-cooled molecules are exploited in quantum technologies as well as in studies of fundamental physical phenomena and ultracold chemistry . The idea of using OCCs in polyatomic molecules builds on the success of laser-cooling of diatomic molecules . The electronic structure of laser-cooled molecules (all the way through hyperfine structure), their applications, and recent experimental advances are thoroughly covered in recent reviews .