The synthesis and characterization of neutral [2 + 1] tricarbonyl mixed-ligand ReI- and 99mTcI-complexes of the general formula fac-[Re/99mTc(CO)3(OO)(isc)] is reported herein. The complexes bear acetylacetone (acac) or curcumin (curc) as monoanionic bidentate (OO) ligands and isocyanide (isc) derivatives of the anticancer agent 2-(4′-aminophenyl)benzothiazole (1) and its 3́-methyl-substituted counterpart (2) as monodentate ligands. The Re complexes were synthesized through the addition of 1 and 2, efficiently prepared in four steps, to the aqua intermediate fac-[Re/99mTc(CO)3(OO)(H2O)], formed by the reaction of the [Et4N]2[Re(CO)3Br3] precursor with the OO bidentate ligands. Ligands 1 and 2 and the corresponding complexes 3-Re and 4-Re (OO acetylacetone), as well as 5-Re and 6-Re (OO curcumin), were fully characterized by elemental analysis, ESI-MS analysis, IR, and NMR. X-ray crystallographic analysis of 3-Re showed that it crystallizes in the monoclinic centrosymmetric space group C2/c with two crystallographically independent molecules in the asymmetric unit that form a dimer through intermolecular π–π stacking interactions between the aromatic rings of the ligand. Synthesis was subsequently transferred at 99mTc-tracer level using the fac-[99mTc(CO)3(H2O)3]+ precursor and the corresponding 3-99mTc–6-99mTc complexes were prepared with a radiochemical yield of >92% and characterized by comparative HPLC analysis using the well-characterized Re complexes as reference. All 99mTc-complexes show good stability against the histidine and cysteine challenge, while their lipophilicity logD7.4 values of 2.55–2.78 fulfil the requisite for high bioavailability. The complexes synthesized bear important pharmacophores, which in complexes 5 and 6 co-exist in the same molecule, representing unique structures currently evaluated for anticancer activity.