Multimodal probesc apable of combining imaging modalities within as ingle molecule are in high demand today as they can providei nformation at both molecular and anatomical levels.H erein, as tudy was conducted on as eries of gallium(III)/lanthanide(III)b is(12-MC-4) metallacrowns( MCs) with the general composition {Ln[12-MC Ga III N(shi) -4]} 2 (iph) 4 (Ln-I x , x = 0, 4, 8, 12), where shi and iph are salicylhydroximate and isophthalate ligands, respectively,o rt heir iodinated derivatives. For Yb-I x ,t he attenuationi nX -ray computedt omography (XCT) imaging and near-infrared (NIR) luminescence properties can be finely tuned by controlled structural modifications based on iodo groups. Solutionso fYb-I x appear to be 22-40 times more efficient as XCT agents in comparison to the commerciallya vailablei obitridol, while providing an intense emission signal in the NIR range with total quantum yields up to 8.6 %, which are amongt he highest values reported so far.T herefore, these molecules are promising potential bimodal agents for combined NIR luminescence and XCT imaging.Supporting information (including experimentaldetails, synthetic procedures,p hysical methods,detailed description of photophysical measurements, and XCT attenuationparameters) and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.