Rheological and rheo‐optical properties are studied for homogeneous blends of the rodlike poly(1,4‐phenylene‐2,6‐benzobisthiazole), PBT, and poly(hexamethylene adipamide), nylon‐66. The linear recoverable creep compliance shows that the distribution of retardation times is similar for all the blends studied, though shifted on the time scale by large variation in the viscosity among the blends. A single‐integral (BKZ‐type) constitutive equation is found adequate to represent the dependence on shear rate of the nonlinear steady‐state viscosity, the recoverable compliance, and the flow birefringence (save for certain anomalous behavior at low shear rate in the latter case). Effects on the viscosity are discussed in terms of a simplified model for behavior when a characteristic rheological time constant is longer for the rodlike (PBT) than for the flexible chain (nylon‐66) component.