Experimental:2-Thienylboronic acid, 3-thienylboronic acid, 2-fomyl-3-thienylboronic acid and 2-acetyl-3thienylboronic acid, tetrakis(triphenylphosphine)palladium(0), were purchased from Sigma Aldrich Chemicals Pvt. Ltd.. Other chemicals were purchased from E. Merck, India, SRL, or Ranbaxy Pvt. Ltd. The bromoaldehydes were synthesized from respective ketones by Vilsmeier-Haack reaction following the standard procedure. Solvents were dried following standard literature procedure. 1 H NMR spectra were recorded on Bruker 500 MHz (at I.A.C.S, Kolkata), Bruker 400 MHz (at I.A.C.S, Kolkata and Kalyani University, Nadia) and Bruker 300 MHz (Calcutta University, Kolkata). 13 C-NMR (125 MHz / 100 MHz / 75 MHz) spectral data were obtained from IACS Kolkata, Kalyani University, Nadia and Calcutta University, Kolkata respectively. ESI mass spectra (HRMS) were recorded on a micro mass Q-TOF mass spectrometer (serial no. YA 263) at I.A.C.S, Kolkata. IR spectra were recorded on JASCO FT/IR 680 PLUS spectrometer. 2-(2-thienyl)cyclooct-1-ene-1-carbalaldehyde (2c): Faint yellow viscous oil; yield: 176 mg (80 %, 0.8 mmol). IR (KBr) ν max : 1660.41 cm -1 ; 1 H NMR (300 MHz, CDCl 3 ): δ 1.40-1.41 (m, 4H), 1.53 (m, ill split, 2H), 1.63 (m, ill split, 2H), 2.48 (t, J = 6.0 Hz, 2H), 2.68 (t, J = 6.3 Hz, 2H), 6.88-6.95 (m, 2H), 7.33 (dd, J = 1.2 Hz & 5.1 Hz, 1H), 9.58 (s, 1H) ppm; 13 C NMR (75 MHz, CDCl 3 ): δ 24.94, 26.09, 26.69, 29.13, 30.02, 36.21, 126.98, 127.81, 130.47, 140.67, 140.76, 153.68, 192.65 ppm; HRMS (ESI, 70 ev): m/z [M+H] + calcd for C 13 H 17 SO: 221.0922; found: 221.0997. 1-(2-thienyl)-3,4-dihydronaphthalene-2-carbaldehyde (2d): Colourless solid; yield: 173 mg (72 %, 0.72 mmol); m.p. 84-86 °C. IR (KBr) ν max : 1654.62 cm -1 ; 1 H NMR (400 MHz, CDCl 3 ): δ 2.60 (dd, J = 7.2 Hz & 9.2 Hz, 2H), 2.79 (dd, J = 7.2 Hz & 14.4 Hz, 2H ), 7.01-7.04 (m, 2 H ), 7.06 ( dd, J = 3.6