The chemistry of the main group metal-halides has been widely explored for several decades owing to the promising physical properties that such compounds often exhibit including semiconductivity, luminescence, and non-linear optical activity.  Our group has been interested in the synthesis of new materials containing complex haloanions of bismuth, lead, copper and silver.  Though reports of many such compounds have appeared in the literature, the majority of these materials contain organic counter-cations for charge balance. We have been interested in the synthesis of mixed-metal halobismuthate materials as synergistic interactions between two different metal-containing species may result in interesting physical properties. We have developed a reliable and versatile solvothermal method for the synthesis of mixed-metal halometallate materials that employ a d-metal coordination cation for charge balance.  The syntheses, single crystal structure determinations, and optical properties including thermochromic behavior of several novel mixed-metal halobismuthate materials will be presented.