Chloromethylphosphonic dichloride reacts with o-aminophenol in the presence of triethylamine to form 2-chloromethyl-1,3,2-benzoxazaphospholine 2-oxide and 2-chloromethyl-2,2'-spirodi[1,3,2-benzoxazaphospholine] in a 1 : 1 ratio. 3-Diethylaminomethyl-2-ethoxy-1,3,2-benzoxazaphospholine reacts with o-aminophenol to form 2-diethylaminomethyl-2,2'-spirodi[benzo-1,3,2-oxazaphospholine]. The crystal and molecular structures of the synthesized spirophosphoranes were determined by single crystal X-ray diffraction.