This study investigates the seasonal, nonlinear, and event-based relationship between aerosol optical depth (AOD) and lightning activity over Iran in 2000–2023 by spatiotemporally matching Lightning Imaging Sensor (LIS) observations from the TRMM and ISS missions with the MAIAC product. Breakpoint analysis, event-based distributions, and non-parametric methods provide a physical–statistical framework for understanding aerosol–convection–lightning interactions in arid and semi-arid climates, with relevance to lightning hazard assessment. Analyses used normalized probability density functions (PDFs), breakpoint identification, and non-parametric correlations, while breakpoint uncertainty was estimated using a day-level block bootstrap accounting for within-day clustering. Robustness was evaluated using the MAIAC AOD_QA layer, conditional ERA5 analyses, and separate TRMM-LIS and ISS-LIS analyses. Both LIS missions exhibited peaked event-based distributions, although breakpoint values differed, particularly in autumn. Because the dataset is event-based, the PDFs do not represent lightning occurrence probabilities or rates. Given differences in sampling and observation opportunities and the lack of mission-specific exposure normalization, TRMM-LIS versus ISS-LIS was interpreted solely as a sensitivity analysis. Lightning-associated AOD distributions exhibited a peaked structure in all seasons; lightning events were predominantly associated with low-to-moderate AOD values, while the relative frequency of lightning-associated observations decreased at higher AOD levels. Breakpoints were highest in summer (AOD47 = 0.27, AOD55 = 0.20, CWV = 1.52) and lowest in winter (AOD47 = 0.18, AOD55 = 0.15, CWV = 0.71), suggesting seasonal displacement related to thermodynamic conditions. Both Mild and Strict QA analyses preserved the seasonal pattern of AOD breakpoints, and primary BP estimates for all season–wavelength combinations fell within the corresponding 95% confidence intervals under both QA criteria. Strong negative Spearman coefficients (ρ = −0.95 to −0.85) indicated a dominant decreasing trend in the relative frequency of lightning-associated observations with increasing AOD over the active data range; however, these coefficients alone were not considered evidence of nonlinear or threshold behavior.