The title compounds, [Co2(C8H11BrO3)(CO)6], (1), and [Co2(C12H16Br2O4)(CO)6], (2), result from the replacement of two carbonyl ligands from dicobalt octa-carbonyl by the alkynes 4-hy-droxy-but-2-ynyl 2-bromo-2-methyl-propano-ate and but-2-yne-1,4-diyl bis-(2-bromo-2-methyl-propano-ate), respectively. Both mol-ecules have classic tetra-hedral C2Co2 cluster cores with the Co(II) atoms in a highly distorted octa-hedral coordination geometry. The alkyne ligands both adopt a cis-bent conformation on coordination. In the crystal structure of (1), classical O-H⋯O and non-classical C-H⋯O contacts form inversion dimers. These combine with weak O⋯O and Br⋯O contacts to stack the mol-ecules into inter-connected columns along the b-axis direction. C-H⋯O and C-H⋯Br contacts stabilize the packing for (2), and a weak Br⋯O contact is also observed. Inter-connected columns of mol-ecules again form along the b-axis direction.