Being influenced by both evolving collectivity and single-particle excitations, exotic nuclei beyond the ¹³²Sn are studied in several experimental attempts. Here, we present the systematics on recent isomeric lifetime studies on very-neutron rich ^136,140Sb and ¹⁴²I isotopes in the μs range using the EURICA spectrometer at the RIKEN/RIBF beam factory and first lifetime studies in the less-neutron-rich _136,138I isotopes in the sub-ns range using the EXILL/FATIMA spectrometer at the ILL.