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Bay functionalized perylene diimide substituted with pyridine isomers, (2-pyridine (2HMP-PDI), 3-pyridine (3-HMP-PDI) and 4-pyridine (4-HMP-PDI)) have been synthesized and explored for selective coloro/fluorimetric sensing of heavy transition metal ions. HMP-PDIs showed strong NIR absorption (760-765 nm) in DMF. The absorption and fluorescence of HMP-PDIs have been tuned by make use of pyridine isomers. Reddish-orange color was observed for 2-HMP-PDI (λ = 437, 551, 765 nm) whereas 4-HMP-PDI exhibited light green (λ = 432, 522, 765 nm). 3-HMP-PDI showed orange-yellow (λ = 431, 524, 762 nm). The fluorescence spectra of 2-, 3- and 4-HMP-PDI showed λ at 585, 538, 546 nm, respectively. Interestingly, HMP-PDI dyes showed selective color change (intense pink color) and fluorescence quenching for Fe and Al metal ions in DMF. Absorbance spectra revealed complete disappearance of NIR absorption and intensification/appearance of new peak at lower wavelength. The concentration dependent studies suggest that 4-HMP-PDI can detect up to 36.52 ppb of Fe and 43.12 ppb of Al colorimetrically. The interference studies in presence of other metal ions confirmed the good selectivity for Fe and Al. The mechanistic studies indicate that Lewis acidic character of Fe and Al ions were responsible for selective color change and fluorescence quenching.