The ability to tag proteins has boosted the emergence of generic molecular methods for protein functional analysis. Fluorescent protein tags are used to visualize protein localization and affinity tags enable the mapping of molecular interactions by, for example, tandem affinity purification (TAP) or chromatin immunoprecipitation (ChIP). To apply these widely used molecular techniques on a single transgenic plant line, we developed a multifunctional TAP tag, named GSyellow, which combines the streptavidin-binding peptide (SBP) tag with citrine yellow fluorescent protein (cYFP). We demonstrated the versatility of the GSyellow tag in the dicot Arabidopsis thaliana (Arabidopsis) using a set of benchmark proteins. For proof-of-concept in monocots, we assessed the localization and dynamic interaction profile of the leaf growth regulator ANGUSTIFOLIA3 (ZmAN3), fused to the GSyellow tag, along the growth zone of the Zea mays (maize) leaf. To further explore the function of ZmAN3, we mapped its DNA-binding landscape in the growth zone of the maize leaf through ChIP-seq. Comparison to AN3 target genes mapped in the developing maize tassel or in Arabidopsis cell cultures, revealed strong conservation of AN3 target genes between different maize tissues and across monocots and dicots, respectively. In conclusion, the GSyellow tag offers a powerful molecular tool for distinct types of protein functional analyses in dicots and monocots. As this approach involves transforming a single construct, it is likely to accelerate both basic and translational plant research.