The polydentate phosphinoamines 1,3-{(Ph2P)(2)N}(2)C6H4 and 2,6-{(Ph2P)(2)N}(2)C5H3N have been prepared in a single step from the reaction of the amines 1,3-(NH2)(2)C6H4 or 2,6-(NH2)(2)C5H3N with Ph2PCl in presence of Et3N (1:4:4 molar ratio) in CH2Cl2. Reaction of 1,3-{(Ph2P)(2)N}(2)C6H4 or 2,6-{(Ph2P)(2)N}(2)C5H3N with elemental sulfur or selenium in CH2Cl2 affords the corresponding tetrasulfide or tetraselenide, respectively, in good yield. The complexes [1,3-{Mo(CO)(4)(Ph2P)(2)N}(2)(C6H4)] and [2,6-{Mo(CO)(4)(Ph2P)(2)N}(2)(C5H3N)] were prepared from the reaction reaction of these phosphinoamines with [Mo(CO)(4)(nbd)] (nbd = norbornadiene) in toluene, and the structure of the latter complex has been determined by single-crystal X-ray diffraction analysis.