We develop a comprehensive continuum model capable of treating both electrostatic and structural interactions in liquid dielectrics. Starting from a twoorder parameter description in terms of charge density and polarization, we derive a field-theoretic model generalizing previous theories. Our theory explicitly includes electrostatic and structural interactions in the bulk of the liquid and allows for polarization charges within a Drude model. In particular, we develop a detailed description of the boundary conditions which include the charge regulation mechanism and surface polarization. The general features for solving the saddle-point equations of our model are elucidated and future applications to predict and validate experimental results are outlined.