We report here synthesis and characterization of BODIPY-chlorin arrays containing a chlorin subunit, with tunable deep-red (641–685 nm) emission, and one or two BODIPY moieties, absorbing at 504 nm. Two types of arrays were examined: one where BODIPY moieties are attached through phenylacetylene linker at the 13- or 3,13-positions of chlorin, and a second type where BODIPY is attached at the 10-position of chlorin through an amide linker. Each of the examined arrays exhibits an efficient (≥ 0.80) energy transfer from BODIPY to chlorin moiety in both toluene and DMF and exhibits intense fluorescence of chlorin upon excitation of BODIPY at ~ 500 nm. Therefore, the effective Stokes shift in such arrays is in the range of 140–180 nm. Dyads with BODIPY attached at the 10-position of chlorin exhibit a bright fluorescence in a range of solvents with different polarities (i.e. toluene, MeOH, DMF, and DMSO). In contrast to this, some of the arrays in which BODIPY is attached at the 3- or at both 3,13-positons of chlorin exhibit significant reduction of fluorescence in polar solvents. Overall, dyads where BODIPY is attached at the 10-position of chlorin exhibit ~5-fold brighter fluorescence than corresponding chlorin monomers, upon excitation at 500 nm.

BODIPY-hydroporphyrin energy transfer arrays allow for development of family of fluorophores featuring a common excitation band at 500 nm, tunable excitation band in deep red/near-infrared window, and tunable emission. Their biomedical applications are contingent upon retaining their optical properties in aqueous environment. Amphiphilic arrays containing PEG-substituted BODIPY and chlorins or bacteriochlorins were prepared and their optical and fluorescence properties were determined in organic solvents and aqueous surfactants. The first series of arrays contains BODIPYs with PEG substituents attached to the boron, whereas in the second series, PEG substituents are attached to the aryl at the meso positions of BODIPY. For both series of arrays, excitation of BODIPY at 500 nm results in an efficient energy transfer to and bright emission of hydroporphyrin in deep-red (640–660 nm) or near-infrared (740–760 nm) spectral windows. In aqueous non-ionic surfactants (Triton X-100 and Tween 20) arrays from the second series exhibit significant quenching of fluorescence, whereas properties of arrays from the first series are comparable to those observed in polar organic solvents. Reported arrays possess large effective Stokes shift (115 – 260 nm), multiple excitation wavelengths, and narrow, tunable deep-red/near-IR fluorescence in aqueous surfactants, and are promising candidates for a variety of biomedical-related applications.