A graphical method has been developed for the reliable detection of cooperativity in polymetallic complexes involving intra- and intermolecular complexation processes. The method relies on the determination of the partial occupancy r(ALn), which represents the average number of metals bound per preassembled receptor AL(n), made up of n ligands bound to a linker A. We observe nonlinear, i.e., nonstatistical, Scatchard-like plots (r(ALn),/[M] VS r(ALn)) for metal-binding in double-stranded helicates. The present concept is extended to a virtual, pre-organized receptor L-n, in which no specific linker is involved. Applications to several polymetallic helicates reveal the presence of negatively cooperative processes attributed mainly to intermetallic repulsions, in agreement with recent thermodynamic models.