Synthesis of a series of novel iminophosphorane derivatives of piperazine was accomplished through Staudinger reaction in high yields (70-80%). In the first step, 1-(4-fluorophenyl) piperazine (1) and 1-(2-pyrimidyl) piperazine (6) were reacted with chlorodiphenylphosphine (2) in the presence of triethylamine (TEA) in dry THF at low temperature under N2 atmosphere to form the compounds (3) and (8). These on further reaction with a series of alkyl azides (4a-k) gave the corresponding iminophosphorane derivatives (5a-k). Their chemical structures were established by IR, 1H, 13C, 31P-NMR, mass spectral studies and elemental analyses. All the titled compounds (5a-k) showed promising anti-microbial activity.