The present invention provides novel inhibitors of cystathionin gamma synthase (CGS), their use as selective and non-selective herbicides, agricultural and non-agricultural herbicides, herbicides in integrated pest management, herbicides for gardening, clearing waste ground, clearing industrial or constructions sites, clearing railways and railway embankments, pesticide, fungicide, agricultural plant stimulant or antimicrobial agent. Also provided is a method for the control of undesired vegetation or clearing areas from the undesired vegetation comprising applying to the locus of said undesired vegetation, to the undesired plants or to a habitat thereof, a herbicidally effective amount of the compound of the present invention.