Researchers have introduced C-MuMOInstruct, a dataset focused on multi-property optimization in drug design.GeLLMO-Cs, a series of instruction-tuned Large Language Models (LLMs), have been developed to perform targeted property-specific optimization.Experiments across tasks show that GeLLMO-Cs outperform strong baselines, with up to 126% higher success rate.GeLLMO-Cs demonstrate impressive generalization to novel tasks and unseen instructions, aiming to support diverse optimizations in drug design.