Present work consists of study of β-Lactamase (BLase) inhibitory potential of phytochemicals from Apocynaceae & Compositae families and Ketophosph(on)ates. For this study; an easy, efficient & economical method was developed, used successfully and published. In this study, thirty two compounds were prepared and characterized by EIMS & 1 H-NMR. These compounds comprise of: Diethyl (2-oxo-2-phenylethyl) phosphonate(1), Diethyl [(E)-1-benzoyl-2-phenylvinyl] phosphonate(2), Diethyl[(E)- 1-benzoyl-2-(2-hydroxyphenyl) vinyl] phosphonate(3), Diethyl [(1E,3E)-1-benzoyl-4- phenylbuta-1,3-dien-1-yl] phosphonate(4), Diethyl [(1E)-1-benzoyl-2-phenylprop-1- en-1-yl]phosphonate(5), Diethyl [(E)-1-benzoyl-2-(4-hydroxy-3-methoxyphenyl) vinyl] phosphonate(6), Diethyl benzyl phosphonate(7), Diethyl [2-(2-hydroxyphenyl)- 2-oxo-1-phenylethyl] phosphonate(8), Diethyl [(3E)-2-oxo-1,4-diphenylbut-3-en-1- yl] phosphonate(9), Diethyl(2-oxo-1,2-diphenylethyl) phosphonate(10), Diethyl (2,4- dioxo-1-phenylpentyl) phosphonate(11), Diethyl (2,4-dioxo-1,4-diphenylbutyl) phosphonate(12), Ethyl (diethoxyphosphoryl) acetate(13), Diethyl (oxiran-2- ylmethyl) phosphonate(14), Diethyl[2-(2-hydroxyphenyl)-1-oxiran-2-yl-2-oxoethyl] phosphonate(15), phosphonate(16), 6-Diethyl Diethyl [(3E)-1-oxiran-2-yl-2-oxo-4-phenylbut-3-en-1-yl] (1-oxiran-2-yl-2-oxo-2-phenylethyl) phosphonate(17), Diethyl (1-oxiran-2-yl-2,4-dioxopentyl) phosphonate(18), Diethyl (1-oxiran-2-yl-2,4- dioxo-4-phenylbutyl) phosphonate(19), Diethyl (2-nitrobenzyl) phosphonate(20), six derivatives (21-26) containing the Tetraethyl ethane-1,2-diylbis (phosphonate) motif, Diethyl methylphosphonate(27), phosphonate(28), Diethyl Diethyl Diethyl [2-(2-hydroxyphenyl)-2-oxoethyl] [(3E)-2-oxo-4-phenylbut-3-en-1-yl] (2-oxo-2-phenylethyl) phosphonate(30), phosphonate(29), Diethyl(2,4-dioxopentyl) phosphonate(31) and Diethyl (2,4-dioxo-4-phenylbutyl) phosphonate (32). Seventeen compounds showed BLase inhibition activity. The compounds 1, 12, 29 & 32 were found more active than Clavulanic acid (used as standard). Extraction and bioassay guided isolation of Cichorium intybus resulted in the purification and identification of ten compounds: [Lupeol (33), β-Sitosterol(34), p- hydroxy phenyl acetic acid(35), Isovanillic acid(36), Syringic acid(37), Vanillic acid(38), Esculetin(39), Scopoletin(40), Umbelliferone(41) and Kaempferol(42)]. Stigmasterol(43) was the only compound isolated from Ageratum conyzoides but six compounds: [Conessine(44), Kurchinin(45), Conimine(46), Kurchamine(47), Holaromine(48) & Kurchessine(49)] were extracted from Holarrhena antidysenterica. viiiHowever two compounds: [Lupeol(32) & Campesterol(50)], were extracted from Carissa opaca while Quercetin(51) & Kaempferol(42) were isolated from Alstonia scholaris. β-Sitosterol(34), α-Amyrin(52) & Ursolic acid(53) came out of Calotropis procera. All the phytochemicals were subject to BLase inhibition study. In general these phytochemicals showed poor activity however Kurchamine(47), Holaromine(48) and Quercetine(51) were relatively more active in this respect.