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Synthetic strategies were developed for the preparation of indolo‐imine boron difluoride (IIBD) dyes based on indolo[3,2‐b]carbazole structures. Four new IIBD dyes were synthesized and were subsequently converted into the corresponding ‐BPh2/‐BOR2 and N‐t‐Boc/N‐benzoyl derivatives. The photophysical properties of all dyes were determined in both solution and solid media. All dyes absorb in the UV/Vis region, show negative solvatochromism, and are fluorescent in both media. The absorbance and fluorescence properties of the dyes can be tuned over a wide range by synthetic modifications. These findings are rationalized by theoretical calculations that correspond well to the experimental shifts, explain the negative solvatochromism, and allow quantification of charge transfer (CT). Similarly, the HOMO–LUMO energies measured by CV are in good agreement with the theoretically calculated values. Interestingly, the energy gaps of the dyes can also be tuned by structural modulations using the developed chemical route. Charge transport properties of the dyes were checked and showed that the N‐benzoyl derivative has the highest hole mobility which is useful for organic field effect transistor (OFET) applications. In addition, easy cellular uptake of the dyes, their low toxicity and high stability inside the cells associated with bright fluorescence in the cytoplasm will be useful for their future application as cellular imaging agents. All of these aspects highlight the interest of this new class of dyes.

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In view of the inadequacy of neuroblastoma treatment, five hydroxystilbenes and resveratrol (Resv) were screened for their cytotoxic property against human neuroblastoma cell lines. The mechanism of cytotoxic action of the most potent compound, trans-4,4’-dihydroxystilbene (DHS) was investigated in vitro using human neuroblastoma cell lines. DHS was also tested in a mouse xenograft model of human neuroblastoma tumor. The MTT, sub-G1, annexin V and clonogenic assays as well as microscopy established higher cytotoxicity of DHS than Resv to the IMR32 cell line. DHS (20 μM) induced mitochondrial membrane permeabilization (MMP) in the cells, as revealed from JC-1 staining, cytochrome c and ApaF1 release and caspases-9/3 activation. DHS also induced lysosomal membrane permeabilization (LMP) to release cathepsins B, L and D, and the cathepsins inhibitors partially reduced MMP/caspase-3 activation. The ROS, produced by DHS activated the p38 and JNK MAPKs to augment the BAX activity and BID-cleavage, and induce LMP and MMP in the cells. DHS (100 mg/kg) also inhibited human neuroblastoma tumor growth in SCID mice by 51%. Hence, DHS may be a potential chemotherapeutic option against neuroblastoma. The involvement of an independent LMP as well as a partially LMP-dependent MMP by DHS is attractive as it provides options to target both mitochondria and lysosome.

Highly sensitive and selective near-infrared fluorescent bioprobes for serum albumin detection and quantification is in high demand for biomedical applications. Herein, we report a near-infrared emitting BODIPY-O-glycoside dye as a...