Crystallization of copper(I) halide: triphenylphosphine mixtures from 1,2-diaminoethane (en = ethylenediamine) has yielded adducts 1:1:2 CuX:PPh3:en stoichiometry (X = Cl or I); the chloride and iodide have been characterized by room temperature single crystal X-ray structure determinations; the iodide is a hemisolvate. In both cases, the complex is ionic, the four coordinate CuPN3 environment comprising both bidentate and unidentate en, i.e [(κ2-N,N’-en)(κ1-N-en)(PPh3)Cu]+X−. In each case, there are two crystallographically independent cations which are conformationally different. Adduct [(PPh3)(κ 2-N,N’-en)(κ 1-N-en)Cu]Cl is very unstable and decomposes on air, whereas [(κ 2-N,N’-en)(κ 1-N-en)(PPh3)Cu]I is sufficiently stable both in the solid state and in solution to be characterized. Adducts of similar stoichiometry are obtained with silver(I) nitrate, and with silver(I) perchlorate with PCy3, and 1,2-diaminopropane (pn): the single crystal X-ray structure determinations confirm the ionic/mononuclear formulations [(κ2-N,N’-en)(κ1-N-en)(PPh3)Ag]NO3 and [(κ2-N,N’-en)(κ1-N-en)(PCy3)Ag]ClO4 that persist also in acetonitrile, as confirmed by conductance values typical of 1:1 electrolytes in this solvent.