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Recently, one-dimensional (1D) II–VI semiconductor nanostructures have attracted much interestdue to their novel optical and electronic properties. CdS(cadmium sulfide), as a typical wide band-gapII–VIsemiconductor, has a band-gap of 2.42 eV at room temperature.The properties of CdS nanostructural materials are remarkably dependent on their morphology (including size, shape and dimension).With crystal size decreasing,the energy band of semiconductor nanocrystallites evolves from sequential to discrete energy levels, which causes semiconductor nanocrystallites display optical, electronic and structural properties to be different fromtheir bulk counterparts.Since manyfundamental properties ofCdShave been expressed as a function of size and shape, controlling the size and shape of semiconductor nanocrystallites would provide opportunities of tailoring properties of materials. Large-scale CdS nanofibers with uniform diameter and high aspect ratios were synthesized using a simple solvothermal route that employed CdCl2andS powder as starting materials and ethylenediamine (en) as the solvent.This route is simple, reproducible, nontoxic, and does not need complicated surfactants, and it can be used to synthesize other sulfides.The dielectric constant of ethylenediamine is 13.82. It is known that, the aspect ratio of solvothermally prepared nanostructures increases with decreasing dielectric constant of the solvent. Therefore, ethylenediamine as a solvent with low dielectric constantand relatively low boilingtemperature is in favor of one-dimensional growth and, therefore, formation of CdS nanofibers.Thesulfur sourcealsohave a great influence on the morphology andcrystalstructure of CdS.Compare with other sulfur sources, such asthiourea, thiosemicarbazide, Na2S and Na2S2O3,element sulfur is a facile sulfur source. The controllable contents of CdS nanostructures have been tunedby changing the reaction time andtemperature.Based on the results, the size of the CdS nanorods synthesized in ethylenediamine increases with the increase of reaction time or temperature, and the crystallinity is also further improved.Wearchivedtheoptimalcondition of reaction time andtemperatureby repeatthesynthesisby employing arangeofreaction time andtemperatureand alsosuccessfully controltheaspect ratioof CdS byemploying biopolymers(Silk Fibroin, Chitosan andPVA)as thetemplate.We present apolymer-controlled growth method for fabricating CdS nanofibersand nanorods with high aspect ratios via solvothermal rout.Solvothermal route is one of the most effective synthetic methods for synthesizing 1D CdS. It is a convenient and controllable process and is less energy consuming.In comparison to other solution-based methods, highly pure and clean nanostructures with ahigh degree of crystallinity can be produced by the solvothermal route. X-ray diffraction (XRD) pattern showsthat the products are hexagonal structure CdS nanofibers and nanorods.Resultsfrom the FE-SEM and TEM images showCdS prepared in optimal condition contain CdS nanofiberswithdiameter of 35 nm and length up to 1.5μm.The optical properties of the products were characterized by optical absorption spectra. The result from Uv-vis absorption shows a blueshifting compared with the characteristic absorption of the corresponding bandgap of the bulk CdS. A possible formation mechanism ofCdSnanofibersand nanorodsis discussed.