Group 2 bis-element sandwiches formed by homoleptic open sandwiches with formula C 5 H 7 –M–M–C 5 H 7 and C 4 H 4 P–M–M–C 4 H 4 P (M = Be, Mg, and Ca) have been studied at the B3LYP/cc-PVDZ and BP86/6-311G(d,p) levels of theory. The predicted M–M bond distances are much shorter than in the equivalent isolated M–M dimer and indicate substantial Be–Be, Mg–Mg, and Ca–Ca bonding. An NBO analysis shows that each M–M unit contains a single covalent bond and that the unit is linked to the open pentadienyl and phospholyl ring via ionic bonds. We thus predict that these new compounds are viable synthetic targets.