In-plane anisotropic optical and electrical properties of layered ReS2 crys
tals are reported. The optical anisotropic effects for E parallel to 6 pola
rization and E perpendicular to b polarization were studied through polariz
ation-dependent piezoreflectance and optical absorption measurements. The r
esistivity perpendicular to the b-axis was shown to be several times larger
than that along the b-axis.