Learning nature's approach to modulate photophysical properties of NIR porphyrinoids by fine-tuning beta-substituents including the number and position, in a manner similar to naturally occurring chlorophylls, has the potential to circumvent the disadvantages of traditional "extended pi-conjugation" strategy such as stability, molecular size, solubility, and undesirable pi-pi stacking. Here we show that such subtle structural changes in Pt(II) or Pd(II) cis/trans-porphodilactones (termed by cis/trans-Pt/Pd) influence photophysical properties of the lowest triplet excited states including phosphorescence, Stokes shifts, and even photosensitization ability in triplet triplet annihilation reactions with rubrene. Prominently, the overall upconversion capability (eta, eta = epsilon.Phi(UC)) of Pd or Pt trans-complex is 10(4) times higher than that of cis-analogue. Nanosecond time-resolved infrared (TR-IR) spectroscopy experiments showed larger frequency shift of nu(C=O) bands (ca. 10 cm(-1)) of cis-complexes than those of trans-complexes in the triplet excited states. These spectral features, combining with TD-DFT calculations, suggest the strong electronic coupling between the lactone moieties and the main porphyrin chromophores and thus the importance of precisely positioning beta-substituents by mimicking chlorophylls, as an alternative to "extended pi-conjugation", in designing NIR active porphyrinoids.