Mixed bismuth-chalcogen-iron clusters [{EFe3(CO)(9)}Bi](-) [E = Te (1a) or Se (1b)] were produced via the reduction of BiCl3 with [EFe3(CO)(9)](2-) under mild conditions. X-ray analysis showed that both clusters 1a and 1b had a square-pyramidal geometry, where the naked Bi and chalcogen both adopted a distorted trigonal-pyramidal configuration with a stereoactive lone pair. Complexes 1a and 1b can be further functionalized by methylation and metalation, which permits the nucleophilicity of the 6s/5s and 6s/4s lone pairs to be compared. In the metalation, the 6s pair of the Bi atom in 1a and 1b had an extraordinary nucleophilicity toward the unsaturated Cr(CO)(5) fragment, even in the presence of the more chemically active Ss or 4s pair, whereas in the case of methylation, only the 4s pair of Se could be selectively alkylated. Upon oxidation of 1a and 1b with suitable oxidizing agents, NaBiO3 or K2SeO3, Bi-E bonded tetrahedral complexes [{EFe2(CO)(6)}Bi](-) [E = Te (4a) or Se (4b)] were formed by the elimination of one Fe(CO)(3) vertex. X-ray photoelectron spectroscopy, X-ray absorption near-edge structure, and density functional theory (DFT) calculations showed that all of the Bi atoms in these complexes had oxidation states close to +1. Due to the electropositive character of the Bi atom, pronounced induced Bi center dot center dot center dot E inter- and intramolecular interactions were evident in 1a (1b), 4a (4b), and the metalated 3a (3b), where their linear-like center dot center dot center dot Bi center dot center dot center dot E center dot center dot center dot or zigzag-like center dot center dot center dot Bi-E center dot center dot center dot (E = Te or Se) chain or the Bi center dot center dot center dot E center dot center dot center dot E center dot center dot center dot Bi (E = Te or Se) dimeric chain can further expand into the two-dimensional network via nonclassical C-H center dot center dot center dot O(carbonyl) interactions, supported by noncovalent interaction index and DFT calculations. These positively charged Bi-induced Bi center dot center dot center dot E (E = Te or Se) and carbonyl-aided weak interactions can facilitate efficient electron transport within these ternary Bi-E-Fe or quaternary Bi-E-Fe Cr cluster-based frameworks, resulting in semiconducting behavior with surprising ultranarrow energy gaps of 1.01-1.21 eV.