New upper-rim polyphosphorylated calix[4]arenes were designed for decorporation of uranium in case of nuclear contamination. A ligand system containing four preorganized 1-hydroxymethylene-1,1-bisphosphonic acid moieties anchored onto a calix[4]arene platform has been developed. Three calix[4]arene-bisphosphonates were efficiently prepared in multi-step syntheses with a variable carbon chain length