The reaction of LiP(H)Tipp (2a) and KP(H)Tipp (2b, Tipp = C6H2‐2,4,6‐iPr3), which are accessible via metalation of Tipp‐PH2 (1), with bis(4‐tert‐butylphenyl)phosphinic chloride yields Tipp‐P=P(OM)Ar2 [M = Li (3a) and K (3b)]. These complexes show characteristic chemical 31P shifts and large 1JPP coupling constants. These compounds degrade with elimination of the phosphinidene Tipp‐P: and the alkali metal diarylphosphinites M–O–PAr2 [M = Li (4a) and K (4b)]. The phosphinidene forms secondary degradation products (like the meso and R,R/S,S‐isomers of diphosphane Tipp‐P(H)–P(H)Tipp (5) via insertion into a P–H bond of newly formed Tipp‐PH2), whereas the crystallization of [Tipp‐P=P(OLi)Ar2·LiOPAr2·LiCl·2Et2O]2 (i.e. [3a·4a·LiCl·2Et2O]2) succeeds from diethyl ether. The metathesis reactions of LiP(SiiPr3)Tipp and LiP(SiiPr3)Mes (Mes = C6H2‐2,4,6‐Me3) with Ar2P(O)Cl yield Ar*‐P=P(OSiiPr3)Ar2 (Ar* = Mes, Tipp) which degrade to Ar2POSiiPr3 and other secondary products.