Methyl 3-trifluoroacetyl-13 1 -deoxo-pyropheophorbide-a (1) and its derivatives were prepared by modifying naturally occurring chlorophyll-a. The 3-trifluoroacetyl group of the synthetic pigments was reacted with amines in dichloromethane to give the hemiaminal-type adducts bearing blue-shifted absorption bands. The hemiaminal of metal-free chlorin 1 with butylamine was formed more preferably than were those of its metal complexes as well as its C17C18 (porphyrin) and C7–C8 analogs (bacteriochlorin). An increase of the steric hindrance around the nitrogen atom of amines reduced the production of hemiaminals and primary amines possessing a primary alkyl group were selectively detected by absorption spectral change in 1. Polyamines bearing a (2-aminoethyl)amino group were readily added to the trifluoroacetyl group of 1 to afford the hemiaminals stabilized by intramolecular hydrogen bonding of the resulting hydroxy group with the nitrogen atom of the 2-aminoethyl group. Therefore, ethylenediamine was quantitatively analyzed by fluorescence emission spectroscopy and could be quickly detected even at 1 nmol (=0.1 equiv) using 10 −5 M solution (1 mL) of 1 in aerated dichloromethane.