The aggregation of amphiphilic oxyethylated calix[4]arene is studied in the absence and presence of polyethyleneimine. At low calixarene concentrations, large ensembles with a hydrodynamic diameter of about 100 nm are formed and coexist with small (smaller than 10 nm) aggregates, which are observed in the entire concentration range. It is established that calixarene-based systems catalyze the neutral hydrolysis of bis(chloromethyl)phosphinic acid p-nitrophenyl ester, with the catalytic effect being as high as two orders of magnitude in the presence of La(III) ions. The rate of hydrolysis of phosphonates depends on the composition of the supramolecular system. The maximum acceleration exceeds three orders of magnitude in comparison with alkaline hydrolysis of the substrates.