We report the first results of quasi-simultaneous two passband optical monitoring of six quasi-stellar objects to search for micro-variability. We carried out photometric monitoring of these sources in an alternating sequence of R and V passbands, for five radio-quiet quasi-stellar objects (RQQSOs), 0748+291, 0824+098, 0832+251, 1101+319, 1225+317 and one radio-loud quasi-stellar object (RLQSO), 1410+429. No micro-variability was detected in any of the RQQSOs, but convincing micro-variability was detected in the RLQSO on two successive nights it was observed. Using the compiled data of optical micro-variability of RQQSOs till date, we got the duty cycle for micro-variability in RQQSOs is $sim$ 10%. The present investigation indicates that micro-variability is not a persistent property of RQQSOs but an occasional incident.
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