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raphene sheets (mono- and multilayers) were synthesized by chemical vapor deposition and functionalized with various aromatic molecules such as Fe-/Co-porphyrin and Fe-phthalocyanine through π–π interactions. The resulting nanohybrid materials were characterized by Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM) techniques. The presence of physi-adsorbed molecules (Fe-/Co-porphyrin and Fe-phthalocyanine) on the graphene sheet surface is evidenced by spectroscopic and microscopic analyses, which confirm that these molecules are immobilized through electrostatic and π–π interactions. RS confirmed the n- or p-type doping of graphene, according to the chemical nature of those physi-adsorbed molecules. The electrical characteristics of electrolyte-gated graphene field-effect transistors (GFETs) based on nanohybrid materials were subsequently evaluated and demonstrated a charge transfer between the physi-adsorbed molecules and the graphene. All of these results suggest that the electronic structure of graphene can be tailored by doping with aromatic molecules. Density functional theory (DFT) calculations were performed to confirm these observations, Hubert Curien─Fundação para a Ciência e a Tecnologia (FCT) Partnership (PHC-PESSOA 2D GAS SENS). Graphene field-effect transistors were provided through ASCENT+ collaboration from European Union’s Horizon 2020 research and innovation programme, grant agreement 871130. In addition, FCT partially supported UMinho’s research in the framework of the Strategic Funding UIDB/04650/2020. This work was carried out with partial support from LABEX MMCD. The authors acknowledge financial support from the French state managed by the National Research Agency under the Investments for the Future program under the references ANR-10-EQPX-50, pole NanoMAX, and pole NanoTEM. Part of the TEM analysis was carried out at Centre Interdisciplinaire de Microscopie électronique de l’X (CIMEX), which is gratefully acknowledged. The authors acknowledge the help and support from Dr. Simons Hallais for AFM analysis