Phase-change materials (chalcogenide alloys such as GeSbTe) and carbon-based materials (graphene oxide and amorphous carbon) are one of the most promising candidates for the emerging resistive switching memory devices. Under external stimulus, such as voltage or laser pulse, they undergo (partial) phase transition resulting in the change of both electrical properties, i.e. switching between states with low and high resistance, and optical characteristics of the media. Thus, phase-change materials were recently suggested for creating optoelectronic devices (e.g. tunable absorbers, phase modulators, optical memories) and for tunable metamaterials while carbon materials are already widely used for various electrical and optical applications. In this talk I will give an overview of the main research areas of our group and will present some recent results on optical applications of GeSbTe-based (meta)materials and resistive switching studies in graphene oxide.