To determine the energy transfer efficiency (ηsens), one needs the relative and intrinsic quantum yield of that particular complex. Most of the reported cases regarding lanthanide(III) luminescence are comprised of EuIII where detailed analysis regarding determination of radiative lifetime of EuIII can be found (considering A and area or intensity ratio). But, a clear and concise information is hardly observed for other two lanthanide ions SmIII and TbIII who also emit in the visible region. Some have taken tentative values of the same and calculated the intrinsic quantum yields thereon. Finally, they provided the resulting energy transfer efficiency (ηsens) values as obtained. We want to calculate or determine ηsens for ternary tris-diketonate SmIII and TbIII complexes.