The study of water clusters in a confined state has received considerable attention. The simplest among such assemblies of water molecules is the water dimer. Stabilizing this unit at ambient conditions in an appropriate host-template, however, has remained a challenge. Herein, we report 2,6-(diphenylmethyl)-4-iso-propyl-phenyl substituted phosphate diesters (both in their neutral and anionic forms) as molecular templates for hosting the water dimer. The robustness of the water dimer within the neutral phosphate-diester ensemble is remarkable. Even when treated with triethylamine the water dimer is not disrupted, while exclusively the P(O)(OH) unit is deprotonated.