  We have investigated the physical properties of a new layered oxyselenide
Bi$_{2}$YO$_{4}$Cu$_{2}$Se$_{2}$, which crystallizes in an unusual intergrowth
structure with Cu$_{2}$Se$_{2}$ and Bi$_{2}$YO$_{4}$ layers. Electric transport
measurement indicates that Bi$_{2}$YO$_{4}$Cu$_{2}$Se$_{2}$ behaves metallic.
Thermal transport and Hall measurements show that the type of the carriers is
hole-like and it may be a potential thermoelectric material at high
temperatures. First principle calculations are in agreement with experimental
results and show that Bi$_{2}$YO$_{4}$Cu$_{2}$Se$_{2}$ is a quasi-2D metal.
Further theoretical investigation suggests the ground states of the
Bi$_{2}$YO$_{4}$Cu$_{2}$Se$_{2}$-type can be tuned by designing the blocking
layers, which will enrich the physical properties of these compounds.
