Energy transfer from M:PNCs to Rhodamine B is probed by the decrease in emission of PNCs and concurrent increased emission of RhB. And the appearance of iso-emissive point is suggestive of equilibrium between two emissive species (Scheme 2). Herein energy transfer from metal-doped perovskite nanocrystals to Rhodamine B has been systematically investigated by using steady state and time-resolved photoluminescence measurements. Our detailed structural studies document the crystal stiffening by a small doping of Ni/Co which modifies the facet accordingly. We believe this study will serve as a rule of thumb for designing a transition metal-doped perovskite nanocrystals for tuning their photocatalytic activities.