Strong optical responses of two-dimensional (2D) semiconductors like transition metal dichalcogenides (TMDs) draw substantial attention for prospective applications in optoelectronics and photonics. Here, we propose a potentially attractive application avenue via embedding patterns of 2D semiconductors (shaped, e.g., as strips or disks) in planar optical microcavities to engineer photonic modes in the dissipation-free spectral range below the optical gap. While the cavity confines electromagnetic fields to its interior, the high in-plane polarizability of 2D materials causes the appearance of the cavity modes that are bound to the patterned pieces in the lateral directions along the cavity. A TMD strip would then act to guide such bound cavity photons, while a pair of neighboring strips could operate similar to coupled photonic waveguides. Our calculations relying on experimentally measured TMD optical suspectibilities, explicitly demonstrate this type of behavior accompanied by photonic binding energies on the order of 10 meV and micron-scale spatial extents. They indicate that patterned 2D semiconductor structures employed within microcavities could represent a new material platform to enable various functionalities of integrated photonics.