Phenylarsenic(III) dimethoxide derivatives of substituted benzothia-zolines having the general formula PhAs(OMe)2[N(H)C6H4SCR(R)′] where R = CH3, R′ = CH3 (1), R = C2H 5, R′ = C2H5 (2), R = H, R′ = C6H5 (3), R = CH3, R′ = C 6H5 (4) R = CH3, R′ = C6H 4CH3-4 (5), R = CH3, R′ = C 6H4Cl-4 (6), have been synthesized by the reaction of PhAs(OMe)2 (prepared in situ) with substituted benzothiazolines in a 1:1 molar ratio in refluxing benzene solution. These newly synthesized complexes have been characterized by elemental analysis and molecular weight measurements. The spectral studies IR, 1H and 13C NMR show the formation of the additional products in which the nitrogen atom of the benzothiazoline-ring coordinate to the central arsenic atom. A distorted trigonal bipyramidal geometry around arsenic atom has been tentatively proposed for these derivatives. Copyright {\textcopyright} Taylor & Francis Inc.