Per‐O‐methylated β‐cyclodextrin (CD) bearing an iodoacetamide group at the 6‐position was synthesized to functionalize protein surfaces. Bovine serum albumin (BSA) was quantitatively modified with the CD derivative by the SN2 reaction of iodoacetamide with a cysteine residue (Cys34) on the BSA surface. The resultant CD‐functionalized BSA (BSA‐CD) spontaneously dimerized upon addition of an anionic tetraarylporphyrin (TPPS) through the supramolecular 1:2 complexation between TPPS and CD on the protein surface. The BSA‐CD/TPPS complex further complexed with ferric protoporphyrin IX (hemin) in the hydrophobic pockets of albumin to form a hemin/BSA‐CD/TPPS ternary complex in which static fluorescence quenching occurred owing to intramolecular electron transfer from the photoexcited TPPS to hemin. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 11–20, 2012.