The dimeric macrocycles [{P(μ-N^tBu)}₂·LL]₂ [LL = OCH₂C(Me)₂CH₂O (1), 2,6-(NH)₂C₅H₃N (2), 1,2-(NH)₂C₆H₄ (3)] have been obtained by the reactions of the appropriate diols and diamines (LLH₂) with the dimeric phosph(III)azane [ClP(μ-N^tBu)]₂. Under different conditions the reaction of 1,2-(NH₂)₂C₆H₄ with [ClP(μ-N^tBu)]₂ gives the monomer [{P(μ-N^tBu)}₂·{1,2-(NH)₂C₆H₄}] (4) (instead of the dimer 3). Contrary to the literature, the results illustrate that the formation of dimeric macrocycles is common in these reactions and dependent among other factors on the steric demands and length of the organic spacer (LL) as well as the reaction conditions.