We report low-temperature (4)A(2) <- E-2 photoluminescence spectra of nanocrystalline ZnAl2O4/Co(II) as prepared by co-precipitation and subsequent calcination between 600 and 1000 degrees C. The inhomogeneous width and the peak maximum of the electronic origin are strongly dependent on the particle size, e. g. displaying shifts and widths of -88 and 198 cm (1) for 3 nm crystallites. The lineshape of the electronic origin can be simulated by a ligand field (LF) model that is centred around low-symmetry LF contributions, induced by lattice defects. Transition metal ions can be employed as effective spectroscopic probes for particle size and strain and hence for lattice defect densities in nanocrystallites. (C) 2010 Elsevier B. V. All rights reserved.