Ab initio calculations have been carried out in a systematic investigation of P center dot center dot center dot N pnicogen complexes H2XP: NXH2 for X = H, CH3, NH2, OH, F, and Cl, as well as selected complexes with different substituents X bonded to P and N. Binding energies for complexes H2XP:NXH2 range from 8 to 27 kJ mol(-1) and increase to 39 kJ mol(-1) for H2FP:N(CH3)H-2. Equilibrium structures have a nearly linear A-P-N arrangement, with A being the atom directly bonded to P. Binding energies correlate with intermolecular N-P distances as well as with bonding parameters obtained from AIM and SAPT analyses. Complexation increases P-31 chemical shieldings in complexes with binding energies greater than 19 kJ mol(-1). One-bond spin-spin coupling constants (1p)J(N-P) across the pnicogen interaction exhibit a quadratic dependence on the N-P distance for complexes H2XP:NXH2, similar to the dependence of (2h)J(X-Y) on the X-Y distance for complexes with X-H center dot center dot center dot Y hydrogen bonds. However, when the mixed complexes H2XP:NX'H-2 are included, the curvature of the trendline changes and the good correlation between (1p)J(N-P) and the N-P distance is lost.