Complexes of the type (OCH2C(CH3)2CH2OB)2S2P(S)OR (where R=Me,Et,Pri,Bui,Ph,CH2Ph) have beensynthesized by the reactions of 2-chloro-1,3,2-dioxaborinanes and potassium salt of O-alkyl (O-aryl)trithiophosphates in 2:1 molar ratio in refluxing benzene. The product are formed as white or light yellowcoloured monomeric solid, soluble in common organic solvents and exhibit high sensitivity towardsatmospheric moisture. These complexes have been characterized by elemental analysis (C,H,S,B), molecularweight measurement, IR and NMR (1H,11B,31P) spectral studies. On the basis of above studies it is postulatedthat boron is in three coordinated state. The newly synthesized complexes show effectiveness againstpowdery mildew disease at a fixed interval of days. Manuscript profile