Complexes of the type (OCH2C(CH3)2CH2OB)2S2P(S)OR (where R=Me,Et,Pri,Bui,Ph,CH2Ph) have been synthesized 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 yellow coloured monomeric solid, soluble in common organic solvents and exhibit high sensitivity towards atmospheric moisture. These complexes have been characterized by elemental analysis (C,H,S,B), molecular weight measurement, IR and NMR (1H,11B,31P) spectral studies. On the basis of above studies it is postulated that boron is in three coordinated state. The newly synthesized complexes show effectiveness against powdery mildew disease at a fixed interval of days.