Color–magnitude diagrams of the OCs NGC 2192, NGC 2266, NGC 2509, and IC 1369, shown in the G versus (BP − RP) plane. Gray points represent stars within the estimated cluster radius, while red filled circles denote the probable cluster members selected using astrometric and photometric criteria. The PARSEC isochrones plotted correspond to three ages for each cluster, with the central value providing the best fit and the younger and older values illustrating the age uncertainty. The adopted ages (in ﹩\mathrm{log}[{\rm{age}}/{\rm{yr}}]﹩) are 9.00, 9.05, and 9.10 for NGC 2192; 8.85, 8.95, and 9.05 for NGC 2266; 9.05, 9.15, and 9.25 for NGC 2509; and 8.30, 8.40, and 8.50 for IC 1369. These CMD-based fits provide the fundamental cluster parameters used throughout this work. In addition, the stars marked by blue boxes and triangles are found to be consistent with the BSSs identified by V. V. Jadhav et al. (2021) and M. Rain et al. (2021), with two BSSs located in NGC 2192 and two in NGC 2266.