The chemistry of organo-gallium and indium complexes with dithiolate and internally functionalised oxo ligands has been explored. With 1,1-dithiolate ligands both classical and organometallic complexes of gallium and indium, [M(S$^\cap$S)₃], [RM(S$^\cap$S)₂] and [R₂M(S$^\cap$S)] (where R = Me or Et; M = Ga or In; S$^\cap$S = RCS₂, ROCS₂, R₂NCS₂ and (RO)₂PS₂) have been isolated. Reactions of internally functionalised oxo ligands with R₃MR$\cdot$OEt₂ afforded diorganometal complexes [R₂ML]$_n$. Molecular structures of several of these complexes have been established by single crystal X-ray diffraction analyses. Complexes derived from oxo ligands showed photoluminescence. They have been used as alkylating agents for C-C coupling reactions of aryl bromides in the presence of PdCl₂(PPh₃)₂. Indium dithiolate complexes have been used as molecular precursors for the preparation of mono dispersed ẞ-In₂S₃ nanoparticles.