The model of Doi and Ohta for multiphase flow is developed and analyzed from a thermodynamic perspective using the general equation for the nonequilibrium reversible irreversible coupling (GENERIC) formalism. A procedure for obtaining a set of "thermodynamically consistent" transport equations is illustrated. The results demonstrate that the Doi-Ohta model is thermodynamically consistent and is thus a valid set of transport equations for multiphase flow. A modification of the original model is proposed to enable comparison with exact theories and validation with published simulation results, for which reasonable agreement is achieved. Extensions for more complex cases are derived within the GENERIC framework. The derivation demonstrates the ability of the GENERIC formalism to improve the theoretical basis of models for transport in complex fluids.