Targeting the increased Fe3+content in tumors, we propose a novel molecular platform integrated cancer iron chelation therapy for 1H-magnetic resonance imaging (MRI) detection of β-galactosidase (β-gal) activity. Following this idea, we have designed, synthesized, and characterized a series of β-d-galactosides conjugated with various chelators and demonstrated the feasibility of this concept for assessing β-gal activity in solution by 1H-MRI T1and T2relaxation mapping.