Reaction of the lithium salt of 1-(2′-pyridyl)-ortho-carborane, Li[1-R-1,2-C2B10H10] (R = 2′-NC5H4), with sulfur, followed by hydrolysis, gave the mercapto-o-carborane, 1-R-2-SH-1,2-C2B10H10 which forms chiral crystals containing helical chains of molecules linked by intermolecular S–HN hydrogen bonds. The cage C(1)–C(2) and exo C(2)–S bond lengths (1.730(3) and 1.775(2) Å, respectively) are indicative of exo S[double bond, length as m-dash]C π bonding. The tin derivative 1-R-2-SnMe3-1,2-C2B10H10, prepared from Li[1-R-1,2-C2B10H10] and Me3SnCl, crystallises with no significant intermolecular interactions. The pyridyl group lies in the C(1)–C(2)–Sn plane, oriented to minimise the NSn distance (2.861(3) Å). The tin environment is distorted trigonal bipyramidal with axial N and Me. The gold derivative 1-R-2-AuPPh3-1,2-C2B10H10, prepared from Li[1-R-1,2-C2B10H10] and AuCl(PPh3), reveals no NAu interaction in its crystal structure.