New nitrogen-containing phosphorus compounds 1 and 3-5 were prepared by the reaction of a nitrogen-containing phenol with PhPCl2. Hydrolysis of 1 gave an acyclic anionic phosphinate hydrogen bonded to an ammonium component (2). Use of a nitrogen-containing diol with P(OPh)(3) resulted in oxidative addition to give hexacoordinate pentaoxyphosphorus compound 6 exhibiting P-N donor action. X-ray analyses performed on all six phosphorus compounds revealed a variety of geometries extending from three- to six-coordinate with ring sizes varying from five- to ten-membered. The structure of 3 is displaced toward a trigonal bipyramid (TBP) as a result of weak P-N donor action. As a consequence of N-C bond cleavage, 1 forms as a bicyclic phosphorane with the nitrogen atom located at an equatorial site of a TBP. In the formation of the tetracoordinate cyclic phosphinate 5, a P-C bond is formed at the expense of O-C bond cleavage of the reactant diol. H-1 and P-31 NMR spectra indicated that the basic coordination structures were retained in solution. It is concluded that the more elusive donor action found for nitrogen relative to sulfur and oxygen is a consequence of bond cleavage reactions. However, with sufficient phosphorus electrophilicity in higher valent states, P-N donor action is achievable as found in the pentaoxyphosphorane (6) in this study while more modest donor action takes place in the lower coordinate state present in 3.