All melting points were uncorrected. Solvents were dried by standard procedures. The progression of all the reaction was monitored by TLC using hexanes/ethyl acetate mixture as eluent. Column chromatography was carried out on Silica gel (230-400 mesh, Merck) by using increasing polarity. 1 H, 13 C and Dept-135 spectra were recorded in CDCl 3 , DMSO-d 6 , and acetone-d 6 using TMS as an internal standard on a 300 MHz spectrometer at room temperature. Chemical shift values were quoted in parts per million (ppm) and coupling constants (J) were quoted in hertz (Hz). Commercially available 57% hydriodic acid purchased from Avra was used in the reaction (CAS number-10034-85-2). The required keto-acids 6, 1a 10, 1a pthalides 9, 1b 13, 1b 14a-g, 1b-d 14h, 1b 14i, 1d 16-b, 1b-c 19a-b, 1c-d 22a-c, 1b-d bis-phthalides 24a-b, 1b 26a-c, 1b 26d-f, 2 26g-h 2 and keto-acids 28a-h 1a, 2 were prepared adopting the reported procedures. General procedure: Reductive cyclization of keto-acid 6 using HI/P: 5-Hexyl-5H-naphtho[2,3-c]carbazole 7 and naphtho[2,3-b]carbazole 8 To a solution of keto-acid 6 (0.4 g, 1.0 mmol) in glacial acetic acid (30 mL), 57% HI (2.49 mL, 20 mmol) and red phosphorus (0.37 g, 12 mmol) were added and refluxed for 24 h. The red phosphorus was then filtered off. To the filtrate, ice-water (100 mL) was added and the precipitated solid was filtered and washed successively with aq. sodium thiosulphate (30 mL) followed by water (60 mL) and air dried. The crude product was purified by column chromatography (silica gel, hexane) to afford 5-hexyl-naphtho[2,3-c]carbazole 7 (0.144 g, 41%). Further elution of the column (silica gel, 1% EA in hexane) furnished 5-hexyl-5H-naphtho[2,3b]carbazole 8 (0.127 g, 36%) as a yellow solid. 7: mp 104-106 o C (Lit. 4c 104 o C). 1 H-NMR (300