Treatment of Li[BH3ER] (E=Se or Te, R=Ph; E=S, R=CH2Ph) with [Cp*CoCl]2 led to the formation of hydridoborate complexes, [CoCp*PhCp*Coμ-EPhμ-κ2-E,H-EBH3], 1a and 1 b (1 a: E=Se; 1 b: E=Te) and a bis-hydridoborate species [Cp*Coμ-κ2-Se,H-SeBH3]2, 2. All the complexes, 1 a, 1 b and 2 are stabilized by β-agostic type interaction in which 1 b represents a novel bimetallic borate complex with a rare B−Te bond. QTAIM analysis furnished direct proof for the existence of a shared and dative B-chalcogen and Co-chalcogen interactions, respectively. In parallel to the formation of the hydridoborate complexes, the reactions also yielded tetracyclic species, [Cp*Coκ3-E,H,H-E(BH2)2-C5Me5H3], 3 a and 3 b (3 a: E=Se and 3 b: E=S), wherein the bridgehead boron atoms are surrounded by one chalcogen, one cobalt and two carbon atoms of a cyclopentane ring. Molecules 3 a and 3 b are best described as the structural mimic of tetracyclo[4.3.0.02,4.03,5]nonane having identical structure and similar valence electron counts. © 2020 Wiley-VCH GmbH