A comparative study on photophysics of meso-substituted mono- and bis-BODIPY carbazoles

•A comparative study was carried out on the photophysics of mono- and bis-BODIPY (BDP) substituted N-butylcarbazoles (CBZ): CBZ-BDP and CBZ-bisBDP. The molecules show significant fluorescence solvatochromism due to Twisted Intramolecular Charge Transfer (TICT) mechanism.•CBZ-bisBDP shows stronger fluorescence due to the presence of two BODIPY units in the molecule.•CBZ-BDP senses micellar organization, as is seen by its ability to determine the Critical Micelle Concentration (CMC) of sodium deoxycholate (NaDC) in aqueous medium. However, its uptake by HeLa cells is seen to be inefficient.•CBZ-bisBDP shows efficient staining of the cytoplasm of HeLa cells.