In this study, we report a new class of rhodamine-based fluorescent sensors for highly selective and sensitive detection of Pd ions in aqueous medium. A rhodamine-based palladium sensor RPS and a coumarin-rhodamine Förster resonance energy transfer (FRET)-pair based palladium sensor FPS were synthesized with the designed podand ligand for Pd ion recognition. They showed both colorimetric change and fluorometric change in the presence of Pd ion due to the opening of their spirolactam rings. Both chemosensors are highly selective to Pd over the other 24 different metal ions and they are selective to palladium species in +2 oxidation state, RPS showed a 70-fold fluorescent turn-on while FPS showed a 1.75-fold ratiometric change at I/I. Furthermore, RPS showed low cell cytotoxicity and it was successfully used to image Pd in BEAS-2B lung epithelial cells. © 2019 Elsevier Science. All rights reserved.