This chapter reviews the application of phase-field theories to polymer systems where chain conformations are not explicitly treated. It introduces the theoretical background of phase-field models, highlighting strategies for enhancing accuracy via additional state variables or optimized phenomenological functions. The chapter covers applications to polymer blends, including coupling with chemical reactions,hydrodynamics, and shear flows, as well as modeling chain connectivity and entanglements. It further extends to polymer liquid crystals by incorporating orientational order parameters, and to polymer vesicles via Helfrich-type shape descriptions and a discrete-spatial variational method. Theoretical analyses and simulations illustrate diverse morphologies and dynamic behaviors across these systems.