Particle swarm optimization has been integrated with the negative factor counting technique and inverse iteration method for efficient tailoring of quaternary low-bandgap copolymers. To analyze the performance of this methodology, model quaternary copolymers have been designed. Various parameters have been carefully selected while devising this methodology for engineering quaternary polymers. In particular, a swarm size of 40 has been chosen as it is found to impart good exploring skills to the algorithm. Also, the fitness function so chosen is found effective for judicious decision making. Verifying the reliability of this approach, quaternary D–A–D copolymers based on cyclopentadienylene, silole and thiophene donors, and dicyanomethylene and carbonyl acceptors respectively have been tailored. Cyclopentadienylene–carbonyl is obtained as the best D–A couple and is found to be highly desirable for designing low-bandgap polymeric skeletons. DOS curves of the investigated copolymers give a similar qualitative picture of the trends in the electronic properties as obtained from the algorithm. Such an in silico approach efficiently returns optimized results worthy of synthetic trials.