Spintronics based on molecular magnets, in which properties of bulk magnetic materials and molecular quantum effects coexist, has received a lot of attention, with great promise in molecular spin detection and manipulation for information storage and the realization of spin qubits for quantum computing. One of the driving ideas in this research field has been the expected long spin-lifetime in organic semiconductors due to the presence of light atoms such as carbon or hydrogen, a key asset that spintronics had been missing for years.  Graphenoid consisting of hexagonal sp2 hybridized carbons is structurally confined nanoscale graphene segments, including quasi-zero-dimensional nanographenes and quasi-one-dimensional graphene nanoribbons. Due to the quantum confinement effect, graphenoid exhibits non-zero energy gap, emerging as appealing organic semiconductor materials. We are aiming at multi-spin graphenoids with atomically precise structures through bottom-up synthetic strategy. Furthermore, the behaviour of the multiple spins is going to be systematically investigated via the state-of-the-art electron paramagnetic resonance (EPR) techniques, combining theoretical calculations, to build up solid structure-property relationship.