Hypervalent iodonium ylides expeditiously generate carbenes which undergo domino intermolecular C–H activation followed by intramolecular condensation in the presence of N-methoxybenzamide as a starting material and a Rh(III)-catalyst to afford dihydrophenanthridines. KIE studies and DFT calculations were performed to substantiate the mechanistic pathway. To extend the synthetic utilisation, fluorescent pyranoisocoumarins were achieved by using Rh(III)-catalyzed peri-C–H/O–H activation/annulation reactions.