The present invention pertains to compounds and polymers which incorporate a boronic acid sensor group (SG) of the formula (I): wherein: J is independently —CH2— or —CH2CH2—; n is independently 0, 1, 2, or 3; and each RR, if present, is independently a ring substituent; and wherein the ring attachment (i.e., where sensor group is attached) is via the 3-, 4-, 5-, or 6-ring position. Such compounds and polymers are useful in the selective chemical detection and/or quantitation of alpha-hydroxy carboxylic acids, such as lactic acid/lactate and malic acid/malate. The present invention also pertains to methods of preparing such compounds and polymers; methods and assays which employ these compounds and polymers; devices (e.g., holographic sensors) and kits for use in such methods and assays, etc.