A competitive coupling of amide anion over menthyl propionate anion with aryl radicalin photo-S_(RN) 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel-lent yield. In contrast, the expected nucleophilic photo-S_(RN) 1 substitution originating from the carb-anion was observed in the case of t-butyl propionate. According to the proposed mechanisms and MOcorrelation diagrams of the coupling step of nucleophiles with aryl radical, the interesting con-trast is reasonably attributed to the variation in energy gap between π~*c-o and π~*Ar of (ArNu)-Usually, the odd electron of (ArNu)- is weightly populated at π~*c-o, however, the diminished priv-ilege of π~*c-o in menthyl propionate promotes a dominant population of the odd electron at π~*Ar,which leads to the fragmentation of (ArNu)- into the starting carbanion and aryl radical. A competitive coupling of amide anion over menthyl propionate anion with aryl radical in photo-S RN 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel-lent yield. In contrast, the expected nucleophilic photo-S RN, 1 substitution originating from the carb-anion was observed in the case of t-butyl propionate. According to the proposed mechanisms and MOcorrelation diagrams of the coupling step of nucleophiles with aryl radical, the interesting con-trast is reasonably attributed to the variation in energy gap between π ~ * co and π ~ * Ar of (ArNu) -Usually, the odd electron of (ArNu) - is weightly populated at π ~ * co, however, the diminished priv-ilege of π ~ * co in menthyl propionate promotes a dominant population of the odd electron at π ~ * Ar, which leads to the fragmentation of (ArNu) - into the starting carbanion and aryl radical.