Sensitive luminescent probes for phenylglyoxylic acid (PGA), which is a biomarker of ethylbenzene and styrene (EB/S) representing the internal dose of EB/S exposure, have been constructed on the basis of newly designed luminescent coordination polymers (LCPs). Three isostructural LCPs with different lanthanide centers were solvothermally synthesized and fully characterized. All the LCPs 1–3 display strong regulated emissions by the adjustable metal–organic coordination interactions. Among LCPs 1–3, the fabricated LCP 2 can quantitatively detect PGA with the highest sensitivity in physiologically relevant ranges. The mechanism study of luminescent responses toward PGA further explains the excellent sensitivity and selectivity of LCP 2 for sensing PGA. The facile, accurate, fast, and recyclable sensing system relying on LCP materials provides a convenient approach for developing sensing platforms with adjustable emissions for assessment of the intoxication level of EB/S.