Exploring innovative strategies for molecular structuring of dynamic materials that combine self-correcting intrinsic reversibility with the robustness of covalent bonds, has been a long-standing objective from applications perspective in fields ranging from molecular engineering to nanotechnology and interfacial science. To establish dynamic covalent chemistry approaches combined with interfacial polymerization, herein, a distinct synthetic approach is reported to develop disulfide-bridged 2D polymeric C3N3S3 triazine thin-films by interfacial thiol-disulfide dynamic exchange process crosslinking tritopic planar 1,3,5-triazine-2,4,6-trithiol molecular tectons via intermolecular disulfide formation in the presence of I2 vapors at the air/water interface under redox condition. The resulting centimeter-scale polymeric thin-films are covalently cross-linked, dynamic in nature, featuring tunable thickness (6–200 nm) and significant morphological variations are realized under the influence of varying reaction time, concentration and types of reducing agents. Notably, C3N3S3 polymer thin films exhibit a transflectance of around 99.5% in the range from 430 to 1800 nm, show high refractive indices (1.730–1.488) and optical anisotropy with uniaxial negative birefringence. The C3N3S3 free-standing polymer thin-films can be easily transferred to different substrates or possibly into application-relevant forms for device fabrications, making this useful from materials application perspective.