The great deal of novel rare earth based semiconducting lanthanum barium copper oxide La3Ba3Cu6O14 (LBC-336) were synthesized by low temperature molten salt synthesis (MSS) due to "dissolution precipitation mechanism". Here, we reported one pot synthesis of product by direct precipitation from a molten KOH-NaOH mixture at 450 °C and single phase La3Ba3Cu6O14 with tetragonal crystal system. The particle size of 140-200 nm were observed in both PXRD pattern and HRSEM micrographs and it showed a cubic morphology. The semiconducting nature was extracted from various parameters like optical band gap (1.8 eV), AC conductivity (0.70 eV), DC conductivity (0.70 eV), and also Hall effect parameters like the charge carrier concentration values n=6.0×1026 m-3 and it proved as a p-type semiconductor. The electrical phase trasition temperature from ferroelectric to antiferroelectric system (Tm=420 K) and anti-ferroelectric - paraelectric system (depolarization temperature Td=673 K) which attributed to the space charge polarization contributed to the conduction mechanism. The magnetic phase transitions were from ferromagnetic to ferrimagnetic system (Curie temperature (Tc=70 K)) and it led to soft magnetic material and also held good for superconductor application upto 70 K. © 2015 The Chinese Society of Rare Earths.