Compounds of the formula, A--L--B, wherein A is glutamate or a glutamate analog; L is a phosphoramidate or a phosphoramidate analog; and B is serine or a serine analog are described which are potent inhibitors of prostate-specific membrane antigen (PMSA). Such compounds are useful in treatment of prostate cancer; and when chemically attached to a fluorescent dye, can efficiently and selectively label prostate cancer cells for fluorescent imaging.