We present a novel probe design which enables simultaneous electroencephalography (EEG) and near-infrared (NIR) optical imaging to be performed in a manner which is easy to apply, allows for optimum co-registration of the two forms of data and maximizes the number of sensors which can be applied to a given area. Our probe design is evaluated using a dual-modality, tissue-mimicking phantom and by performing a simple functional activation study of the human motor cortex. We successfully acquired NIR optical and EEG data simultaneously for both our phantom and our human motor cortex experiments, clearly demonstrating the effectiveness and suitability of our 'opto-electrode'.