A method of determining that a first target and a second target in a sample are proximal, the method comprising: binding a first modified binding molecule to the first target to form a first complex, wherein, the first modified binding molecule comprises a cleavable bridge component, the cleavable bridge component comprises a cleavage site, a detectable moiety, and a first chemical ligation group, the cleavage site is more proximal to the first modified binding molecule than is the detectable moiety and the first chemical ligation group, the first chemical ligation group is at a terminus of the cleavable bridge component, the first chemical ligation group is stable under physiological conditions; binding a second modified binding molecule to the second target to form a second complex, the second modified binding molecule comprises a non-cleavable bridge component, the non-cleavable bridge component comprises a second chemical ligation group, the second chemical ligation group is at a terminus of the non-cleavable bridge component, the second chemical ligation group is stable under physiological conditions; covalently linking the first chemical ligation group to the second chemical ligation group to form a covalently bonded unit where the first target and the second target are proximal; cleaving the cleavage site of the cleavable bridge component such that the covalently bonded unit is bound to the second modified binding molecule and not the first modified binding molecule; removing cleavable bridge components that are not part of a covalently bonded unit; and making the detectable moiety visible, wherein the first target and the second target are proximal where the detectable moiety is visible. binding a first modified binding molecule to the first target to form a first complex, wherein, the first modified binding molecule comprises a cleavable bridge component, the cleavable bridge component comprises a cleavage site, a detectable moiety, and a first chemical ligation group, the cleavage site is more proximal to the first modified binding molecule than is the detectable moiety and the first chemical ligation group, the first chemical ligation group is at a terminus of the cleavable bridge component, the first chemical ligation group is stable under physiological conditions; binding a second modified binding molecule to the second target to form a second complex, the second modified binding molecule comprises a non-cleavable bridge component, the non-cleavable bridge component comprises a second chemical ligation group, the second chemical ligation group is at a terminus of the non-cleavable bridge component, the second chemical ligation group is stable under physiological conditions; covalently linking the first chemical ligation group to the second chemical ligation group to form a covalently bonded unit where the first target and the second target are proximal; cleaving the cleavage site of the cleavable bridge component such that the covalently bonded unit is bound to the second modified binding molecule and not the first modified binding molecule; removing cleavable bridge components that are not part of a covalently bonded unit; and making the detectable moiety visible, wherein the first target and the second target are proximal where the detectable moiety is visible.