ABSTRACT. Biopolymers are referred to the bio-degradable polymer that is derived from living organisms in nature or synthesized from renewable materials but needs polymerization. There are consisting of monomeric units that bond together through a covalent bond to obtain large molecules. A biopolymeric blend of sodium carboxymethyl cellulose/sodium alginate (Na-CMC/SA) film was prepared by the casting/solvent evaporation method. In addition to the molecular structure, the optical and molecular geometry of the collected films were characterized. XRD of binary blend investigated the interaction and miscibility among two biopolymers. FTIR of the blend spectrum explicated the conferring of the two polymer group’s vibrations. UV/Vis and optical studies appeared a peak in the binary at the wavelength (227 nm) which explained the high combination between two polymers. Molecular geometry clarifies the assignment of vibrational spectra of pure polymers which implied the important role of the (C=O) group as eventful regions for the two polymers. KEY WORDS: Sodium carboxymethyl cellulose, Sodium alginate, Na-CMC/SA, FTIR, XRD, UV/Vis Bull. Chem. Soc. Ethiop. 2022, 36(3), 707-716. DOI: https://dx.doi.org/10.4314/bcse.v36i3.19