Abstract: EuIII and YbIII complexes with the carbazole-dipicolinato ligand dpaCbz2-, namely K3[Eu(dpaCbz)3] and K3[Yb(dpaCbz)3], were isolated. The EuIII complex displayed metal-centered emission upon one-photon excitation with a sensitized emission efficiency of 1.8±0.3%, corresponding to an intrinsic emission efficiency of 46% and a sensitization efficiency of ?sens 3.9%, with an emission lifetime of the emissive state t of 1.087±0.005 ms. The YbIII complex displayed of 0.010±0.001%, and a t of 2.32±0.06 µs The EuIII-centered emission was sensitized as well upon two-photon excitation and a two-photon absorption cross-section s2PA of 63 GM at 750 nm was determined for the complex. The one- or two-photon sensitized emission intensity of the EuIII complex changes by more than two-fold when the solvent viscosity is varied in the range 0.5–200 cP and the emission is independent of dissolved oxygen. The YbIII complex displays a change in emission intensity as well. However, in this case, a dependence of the emission intensity on dissolved oxygen content was observed Ver menos