Temperature dependent luminescence, lifetimes and magnetic circularly polarised luminescence (MCPL) are reported between 1.7 and 80K and in magnetic fields of 0-5T for [Ir(ptz)(3)]. Data analysis reveals the temperature and field dependent behaviour is due to the sublevel structure of the emitting state. We have determined energy separations of Delta E-II,E-I =10 cm(-1) and Delta E-III,E-I =45 cm(-1) between three triplet sublevels, with intrinsic luminescence lifetimes of tau(I) = 160 vs, tau(II) = 10 vs and tau(III) = 800 ns. We compare these with values for the green emitter, [Ir(ppy)(3)] and discuss implications for the excited state geometries. (C) 2015 Elsevier B.V. All rights reserved.