A practical protein-detecting array is desirable for its potential application in proteomics, medical diagnostics, and pathogen detection. Here, we report a novel protein-detecting array based on porphyrins containing peripheral amino acids as protein surface receptors. The array of porphyrin receptors showed a unique pattern of fluorescence change upon interaction with certain protein samples. Both metal and nonmetal-containing proteins and mixtures of proteins gave distinct patterns, allowing their unambiguous identification. The composite pattern for each sample was subjected to principal component analysis (PCA) to generate a clustering map for more practical visualization. Increasing the number of porphyrin receptors from eight to sixteen gave improved resolution, suggesting that this array is expandable to give satisfactory resolution for any given sample system by carefully maximizing the chemical diversity of the receptors.