Compounds with crystalline structures characterized by a network of cages, inside which there are heavy atoms (such as rare earth elements), have proved to be good candidate materials for applications in thermoelectric conversion devices, since the low energy vibrations of these so called host atoms inside the guest cages often result in significantly dampened heat transport, one of the basic requirements of a high efficiency thermoelectric conversion material. Examples of such are compounds in the broad families of intermetallic clathrates and skutterudites. Furthermore, intermetallic compounds based on f-electron elements having particular electronic configurations that induce hybridization between the unstable f-electrons and the conduction electrons often result in the formation of strongly correlated electron ground states at low temperatures, wherein the Seebeck coefficient becomes enhanced, another basic requirement for higher thermoelectric conversion efficiency. These cases are most commonly found in compounds containing Ce and Yb (and to a lesser extent Eu, Sm, Pr). With these considerations in mind, we have chosen to investigate a new family of compounds RM2X8 (R = rare earth; M = transition metal; X = Ge, Al) which seems deserving of more careful consideration since only a few compounds in the family have been reported so far, and most of them have only had their structural properties determined, lacking a basic characterization of the electronic, magnetic and transport behaviors. We will present our results of single crystal grown by flux technique and the structural analyses of some of the members of this family. Preliminary basic characterization in these crystals by susceptibility measurements shows that PrCo2Al8 orders antiferromagnetically at TN = 5 K and exhibits a Curie Weiss behavior at temperatures above 120 K. This work is supported by FAPESP and CNPq.