Metastable triplet states provide a versatile route to optically addressable spin qubits that bridge quantum information science, chemistry, and biology. In this seminar, I will present our recent work establishing metastable triplet states as a new quantum platform, from the first genetically encoded fluorescent-protein spin qubit to surface-scaffolded molecular qubits on two-dimensional materials. I will discuss approaches for optical initialization, coherent control, and spin readout, and show how molecular engineering enables long coherence, surface integration, and operation in biological environments. These advances highlight the potential of metastable triplet states for quantum sensing, hybrid quantum devices, and scalable molecular quantum hardware.