Two families of variously-substituted N-pyrrolylphosphino-N′-arylaldimine ligands, 2-(aryl– NCH) C4H3N–PR2 {3a–d R= Ph; 4a–d R= Pri2N}, have been prepared from the corresponding pyrrolylaldimines 2. The donor characteristics/basicity of P–N-chelating 3 and 4 have been assessed using a combination of 31P {1H} NMR and IR spectroscopies through study of the magnitudes of 1JSeP for the phosphorus (V) selenides 7 and 8, and ...