Nowadays, semiconductor quantum dots (QDs), QDs made composites as well as fluorescence chemosensors have attracted considerable attention due to their potential applications in industry and particularly in biology. In this research, at first three 2- benzothiazole ligands and 2-hydroxy naphthalene-based Schiff base have been designed as fluorophore molecules. The MPA-ZnS QDs were then synthesized by a green route, and selected as inorganic based photoluminescence nano particles to investigate their photoluminescence properties and asses their applications in biological studies after surface modification with the aforementioned ligands. So the three ligands, 2-(2?-hydroxylphenyl) benzothiazole, ( 1 ), 2-(2?,5?-dihydroxyphenyl)benzothiazole, ( 2 ), and (4-benzothiazol-2-yl-phenyl)-dimethyl-amine, ( 3 ) and the Schiff base,(E)-4-((2-hydroxynaphthalen-1-yl)methyleneamino)benzoic acid, ( H 2 L) and MPA-ZnSQDs were characterized by CHN analysis, FTIR, UV- VIS spectroscopy, H NMR, molecular emission spectroscopy, x-ray diffraction, thermogravimetric analysis and SEM. The ligands were then used in ligand exchange reactions to modify the surface of the MPA- ZnSQDs. But, the result of photoluminescence emission studies of related hybrids revealed that the excitation and emission wavelengths of those ligands and ZnSQDs overlap to some extent, and separation of the products and investigation of their applications are not desirable. So an alternative method for functionalization of MPA- ZnSQDs was selected as presented in the following. Indeed, benzothiazole ligands corrosion inhibition properties and the effects of their molecular structural and electrical changes on the corrosion inhibition efficiency were studied by experimental and theoretical methods on mild steel in 1M hydrochloric acid solutions. All results of corrosion testing provided from weight loss and electrochemical methods as well as quantum chemical calculations and molecular dynamic simulations show good corrosion inhibition efficiency for these three compounds. In continuation, 2-hydroxy naphthalene based Schiff base was studied as chemosensor for Al 3+ ions. The existence of both hydroxyl and imine groups in its structure, provide suitable conditions for strong interactions and having coordination potential from N and O to Al 3+ ion. Experimental result of ESI-MS, UV-Vis and fluorescence spectrophotometry in the presence of common metal ions and some anions reveal remarkable sensitivity and selectivity of this chemosensor toward Al 3+ ion with LOD = 6.4 × 10 -7 M. Bio studies show this new Al 3+ selective florescent probe has no serious cytotoxicity on live cells up to 50 ?M concentration, and has the potential of being employed for tracing and imaging Al 3+ ion in vitro . Finally, the hybrid compounds of biopolymer/MPA-ZnSQDs, were prepared by surface modification of MPA-ZnSQDs with the polymer from grafted of PDMEM on sodium alginate. This polymer was synthesized and used for increasing the stability of the particles in water and improving their photoluminescence properties during the investigation of their application as drug delivery system for Doxorubicin. The results of FTIR, UV and fluorescence spectrophotometry, TEM and DLS tests reveal the formation of biopolymer coating on surface of the QDs and the good efficiency of this coatings on the stability and photophysical properties of the particles as well as loading and releasing of DOX under biological media pH conditions. The cytotoxicity tests by MTT assay indicate that the ZnSQDs-Alg-g-PDMA-DOX hybrid may be considered as a suitable candidate for therapeutic applications.