T-BuP(NH2)2 reacts with base-stabilized group 13 tri-hydrides with adduct formation (THF-BH3), with redn. to give t-BuPH2 (Me3N-AlH3) and with elimination of H22 and formation of a metallonitridophosphinate (Me3N-GaH3). In contrast, the reaction with Cp*TiMe3 proceeds with formation of the four-membered heterocycle [t-Bu(H)P(NH)2Ti(Cp*)Me2]. The aluminonitridophosphinate [t-Bu(H)P(NH)2AlMe2]2 reacts with C-H acidic reagents such as ROH, H2O with protonation of the N atom and subsequent formation of t-BuP(NH2)2. This general reaction sequence was used for the synthesis of the first alumino(oxo)nitridophosphinate [t-Bu(H)P(NH)OAlMe2]2. The compds. were characterized by spectroscopic methods (1H, 13C, IR, mass spectrometry) and single crystal X-ray diffraction ([t-Bu(H)P(NH)2Ti(Cp*)Me2] [orthorhombic, Pnma(62), a 8.3331(2), b 11.7086(2), c 18.8583(4) .ANG., V 1839.98(7) .ANG.3, Z 4], [t-Bu(H)P(NH)OAlMe2]2) [triclinic, P.hivin.1(2), a 6.4814(4), b 9.0151(6), c 9.6002(8) .ANG., a 81.073(3), b 85.921(3), g 69.950(4) Deg, V 520.47(6) .ANG.3, Z 1]. [on SciFinder (R)]