The influence of a 2-pyridinyl substituent on the catalytic performance of aryliodide as a catalyst in iodine(III) chemistry was explored. An efficient Lews-base adduct between the pyridine nitrogen and the electrophilic iodine(III) center was identified and confirmed by X-ray analysis. This arrangement was shown to generate a kinetically competent superior catalyst structure for the catalytic dioxygenation of alkenes. It introduces the concept of Lewis-base adduct formation as a kinetic factor in iodine(I/III) catalysis.