Abstract: The present invention relates to a cyclopropenium salt bearing an electron withdrawing group suitable for use as a reagent in cyclopropenylation reactions of formula (I). The invention also relates to a process for their preparation, the use thereof as cyclopropenylation reagent, to an electrophilic aromatic substitution process of cyclopropenylation, and to a process for cyclopropenylation of organometallic substrates using said reagents.