Synthesis and structural elucidation of various electron precise group 5 dimetallaheteroboranes have been described. Room temperature reaction of [Cp2VCl2] with Li[BH3(EPh)], generated from the treatment of LiBH4 center dot THF and Ph2E2 (E = S or Se), for 1 h in toluene, followed by thermolysis, led to the formation of bimetallic complexes [{CpV(mu-EPh)}(2){mu-eta(2):eta(2)-BH3E}], 1 and 2 (1:E = S and 2:E = Se), and [{CpV(mu-SePh)}(2){mu-eta(2):eta(2)-BH(OC4H8)Se}], 3. One of the striking features of these compounds is that they represent a rare class of distorted tetrahedral clusters having bridging hydrogens. Evaluating the skeletal electron pairs and bonding types, compounds 1, 2, and 3 may be considered as isoelectronic with our earlier reported [(CpV)(2)(B2H6)(2)]. In an attempt to synthesize the Nb analogues of 1-3, room temperature reactions of [CpNbCl4] and Li[BH3(EPh)] (E = S or Se) were carried out that afforded compounds [{CpNb(mu-EPh)}(2){mu-eta(2):eta(2)-B2H4E}], 4 and 5 (4:E = S and 5:E = Se). The solid-state X-ray structures of both 4 and 5 exemplify electronically saturated [M2B3] systems, and their geometries are analogous to that of [(Cp*MoCl)(2)B3H7]. For the extension of this work, reaction of [Cp*TaCl4] (Cp* = eta(5)-C5Me5) with Li[BH3(SePh)] was carried out that yielded a tantalaselenaborane cluster [(Cp*Ta)(2)(mu-Se)B3H6Se(C6H5)] (6). All the new compounds have been characterized using H-1, B-11{H-1}, C-13{1H} NMR, UV-vis absorption, and IR spectroscopy, mass spectrometry, and X-ray diffraction studies.