Reactions between ethylenediamine (en) solutions of the intermetallic Zintl phases K3E7 (E = P, As) and a series of homoleptic post-transition metal organometallics such as Cu5(Mes)5, M(C6H5)2 (M = Zn, Cd) and In(C6H5)3 have yielded a family of novel bimetallic cluster anions. These new species were isolated as [K(2, 2,2-crypt)]+ salts in [K(2,2,2-crypt)]4Cu2E14 (E = P (1), As (2)), [K(2,2,2-crypt)]4ZnE14 (E = P (3), As (4)), [K(2,2,2-crypt)]4CdP14·6py (5) and [K(2,2,2-crypt)]2E7InPh2 (E = P (6), As (7)). Species 2, 3, 5 and 6 were crystallographically characterised by single-crystal X-ray diffraction. The stability of all of the cluster anions in solution was confirmed by electrospray mass-spectrometry and by 1H, 13C{1H} and 31P{1H} NMR spectroscopy when possible.