C NMR and electronic spectra. The structure of complexes has been accomplished by single crystal X-ray diffraction. All experimental results confirmed that both complexes have an octahedral geometry around the Mo(VI) central atom, which is coordinated by the donor atoms of the dianionic hydrazone ligand, two oxido groups and oxygen/nitrogen atoms of solvent molecules. Computational studies were also performed using DFT calculations at B3LYP/DGDZVP level of theory. Furthermore, their catalytic activities were investigated on the electrophilic reaction of indole with aldehydes in molten tetrabutyl ammonium bromide (TBAB) to obtain bis(indolyl)methane derivatives.