This study reports a facile approach for the green synthesis of a high-performance magnetic resonance/computed tomography (MR/CT) dual-modal imaging nanoprobe. The probe, designated as NPs-TCZ, is synthesized via one-step self-assembly of two amphiphilic block copolymers, namely, PEG-DTIPA-TCZ and pal-GGGGHHHHD. The NPs-TCZ exhibits a high longitudinal relaxivity (9.60 mM