The phosphor LaInO3:Eu3+ exhibits, in addition to the weak orange-red emission of Eu3+, a broad blue emission whose origin formed the basis for the reinvestigation of luminescence of LaInO 3 and the analogous LaGaO3, well known host lattices for luminescent centers. The results are analyzed based on the luminescence observed for In3+ and Ga3+ in various host lattices. An attempt is made to understand the mechanism of the luminescence of d 10 ions In3+ and Ga3+. © 2005 Elsevier Ltd. All rights reserved.