The studies on growth regulation in black gram cv. ADT (Aduthurai) 5 exhibited significant changes in growth, physiology and yield due to chemicals and plant growth regulators. Foliar application of NAA @ 40ppm at pre-flowering stage influenced growth characteristics by showing increased plant height, more number of branches, higher leaf area index and leaf area duration. But, with regard to physiological parameters, the maximum photosynthetic efficiency was observed in brassinolide @ 0.1ppm treated plants as evidenced by the higher specific leaf weight, chlorophyll content, soluble protein and higher nitrate reductase activity. Among the treatments, brassinolide @ 0.1ppm resulted in higher dry matter accumulation, more number of pods and seeds per plant and thereby maximum seed yield. Seed protein content was also found improved due to brassinoliode application.