[Display omitted] An interesting product divergence in the reaction of trifluorodiazoethane with arylidene-1,3-indanediones is reported. The reaction conducted using 10 mol% of silver carbonate afforded trifluoromethylspiropyrazolines, while with excess of cesium fluoride in methanol, the cycloaddition was followed by nucleophilic ringopening of the spiropyrazoline to afford trifluoromethylated -ca