In this study, we present the successful growth of Nd 3+ -and Ho 3+ -activated Gd3In2Ga3O12 (GIGG) single crystals using the optical float zone (OFZ) technique and determine their luminescence properties. This research offers insights into the distribution of rare-earth dopants within the host matrix, the effect of the host structure and cutoff phonon energies on the optical behaviour of the single crystalline luminescent compounds with two representative lanthanoid ions. Perspectives for other potential activators are further discussed.