This work reports a facile synthesis of aluminium doped higher manganese silicides using a single-step spark plasma assisted in-situ reaction sintering process, which takes only a few minutes as opposed to few hours employing conventional processing methods. Despite employing this cost-effective material processing technique, a figure of merit similar to 0.65 at 873 K was realized, which is comparable to the best value reported thus far. The phase purity, elemental distribution, morphology and structure was investigated employing X-ray diffraction, scanning, transmission electron microscopy and energy dispersive spectroscopy, based on which the thermoelectric performance has been discussed