Efficient and clean synthesis of Schiff base as a new ligand, 6-ethoxy-2-(2-methoxy benzylideneamino)benzothiazole has been synthesized in equimolar reaction of 2-amino-6-ethoxy-benzothiazole with 2-methoxy benzaldehyde using microwave technique. The prepared Schiff base was reacted with some transition metal ions Ni(II), Cu(II), Pd(II), Ag(I) and Au(III) in equimolar ratio (M:L, 1:1) using microwave technique. The stereochemistry and the bonding characteristics of the ligand and its complexes were achieved based on elemental analysis, FT-IR, UV-Vis., 1HNMR and ESR as well as Thermo-Gravimetric Analysis (TGA). The thermal dehydration and decomposition of Ni(II), Cu(II) and Ag(I) complexes were studied kinetically using the integral method applying the Coats–Redfern and Horowitz Metzger equations. The reactivity of ligand and its Au(III) complex were studied against breast carcinoma cell. The antimicrobial activity of ligand and its Ag(I) complex studied against the bacterial (positive and negative) grams and fungal strains.